GeMS validation of GeMSFredWash.gdb

Database path: C:\Users\cconnallon.LANGROUP\Desktop\SEAMLESS MAP - statemap\GeMS GEODATABASE FredWash\GeMS FredWash 100k - submittal package\FredWash_MapPublicationFolder\FredWash_MapDatabaseFolder\GeMSFredWash.gdb
File written by GeMS_ValidateDatabase_AGP2.py, version of 8 July 2021
Mon Nov 1 14:18:10 2021

This file should be accompanied by GeMSFredWash.gdb-ValidationErrors.html, GeMSFredWash.gdb-vFgdcMetadata.txt, and GeMSFredWash.gdb-vFgdcMetadataErrors.txt, all in the same directory.

This database is LEVEL 3 COMPLIANT, pending completion of a peer-reviewed Geologic Names report that includes identification of any suggested modifications to Geolex. The FGDC metadata record for this database has formal errors. Please fix!
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Contents

Compliance Criteria
Content not specified in GeMS schema
MapUnits in DescriptionOfMapUnits table, GeologicMap feature dataset, and other feature datasets
Contents of Nonspatial Tables
    DataSources
    DescriptionOfMapUnits
    Glossary
Database Inventory

Compliance Criteria

LEVEL 1

Criteria for a LEVEL 1 GeMS database are: Databases with a variety of schema may meet these criteria. This script cannot confirm LEVEL 1 compliance.

LEVEL 2--MINIMALLY COMPLIANT

A LEVEL 2 GeMS database is accompanied by a peer-reviewed Geologic Names report, including identification of suggested modifications to Geolex, and meets the following criteria:

2.1 Has required elements: nonspatial tables DataSources, DescriptionOfMapUnits, GeoMaterialDict; feature dataset GeologicMap with feature classes ContactsAndFaults and MapUnitPolys PASS
2.2 Required fields within required elements are present and correctly defined PASS
2.3 GeologicMap topology: no internal gaps or overlaps in MapUnitPolys, boundaries of MapUnitPolys are covered by ContactsAndFaults PASS
2.4 All map units in MapUnitPolys have entries in DescriptionOfMapUnits table PASS
2.5 No duplicate MapUnit values in DescriptionOfMapUnit table PASS
2.6 Certain field values within required elements have entries in Glossary table PASS
2.7 No duplicate Term values in Glossary table PASS
2.8 All xxxSourceID values in required elements have entries in DataSources table PASS
2.9 No duplicate DataSources_ID values in DataSources table PASS

LEVEL 3--FULLY COMPLIANT

A LEVEL 3 GeMS database meets these additional criteria:
3.1 Table and field definitions conform to GeMS schema PASS
3.2 All map-like feature datasets obey topology rules. No MapUnitPolys gaps or overlaps. No ContactsAndFaults overlaps, self-overlaps, or self-intersections. MapUnitPoly boundaries covered by ContactsAndFaults PASS
3.3 No missing required values PASS
3.4 No missing terms in Glossary PASS
3.5 No unnecessary terms in Glossary PASS
3.6 No missing sources in DataSources PASS
3.7 No unnecessary sources in DataSources PASS
3.8 No map units without entries in DescriptionOfMapUnits PASS
3.9 No unnecessary map units in DescriptionOfMapUnits PASS
3.10 HierarchyKey values in DescriptionOfMapUnits are unique and well formed PASS
3.11 All values of GeoMaterial are defined in GeoMaterialDict. GeoMaterialDict is as specified in the GeMS standard PASS
3.12 No duplicate _ID values PASS
3.13 No zero-length or whitespace-only strings PASS

There are 44 warnings

Content not specified in GeMS schema

Some of the extensions to the GeMS schema identified here may be necessary to capture geologic content and are entirely appropriate. Please document these extensions in metadata for the database, any accompanying README file, and (if applicable) any transmittal letter that accompanies the dataset. Other extensions may be intermediate datasets, fields, or files that should be deleted before distribution of the database.

    ContactsAndFaults, field LTYPE
    MapUnitPolys, field PTYPE
    TextFile 00log.txt
    MapUnitOverlayPolys, field PTYPE
    OrientationPoints, field PTTYPE

MapUnits in DescriptionOfMapUnits table, GeologicMap feature dataset, and other feature datasets

MapUnit  DMU  GeologicMap
QalXX
QcXX
QrXX
QtXX
MpXX
MDrXX
DhXX
DfXX
DhbsXX
DmXX
DnmXX
DoXX
DSkhXX
StoXX
SwcXX
SbXX
SmXX
SkXX
SrhXX
StXX
OjXX
OmXX
OmuXX
OmlXX
OcXX
OspXX
OpsXX
OrrXX
OsdfXX
OsfXX
OssXX
CcsgXX
CczXX
CcbXX
CeXX
CwacXX
CwakXX
CwarXX
CtXX
CtdXX
CtbXX
CtfXX
CtbhXX
CaXX
ChXX
ChmXX
ChmaXX
CwoXX
CwmXX
CwbXX
CZlXX
CZlcXX
ZcrXX
ZcraXX
ZcrbXX
ZcrfXX
ZcrpXX
ZcrrXX
ZcdfXX
ZcmXX
ZcmpXX
ZcpXX
Zcp1XX
Zcp2XX
Zcp3XX
ZcplXX
ZcbXX
ZcdXX
ZsrXX
ZsrpXX
ZsrqXX
YglXX
YgtXX
YgbXX
YghXX
YgpXX
JdXX
JTrtmXX
TrgXX
TrgcXX
TrghXX
TrnXX
TrnsXX
TrniXX
TrlXX
TrbXX
TrmpXX
TrmpsXX
TrmtXX
OgwXX
OgfXX
OgfsXX
OgcXX
CfuXX
CflXX
CfaXX
CfrXX
CfrbXX
CfmsXX
CfmXX
CarXX
CuXX
CuqXX
CsqXX
CZwmXX
CZscbXX
CZschpXX
CZsclXX
CZscmXX
CZscmpXX
CZscqXX
CZscqpXX
CZscsXX
CZscsrXX
CZsctpXX
CZiXX
CZiqXX
CZibXX
CZicXX
CZilXX
CZimXX
CZipXX
CZmbXX
CZmbqXX

Contents of Nonspatial Tables

DataSources

OBJECTID Source Notes URL _ID
5 American Geological Institute, 2012, Glossary of Geology --- https://www.americangeosciences.org/ DS1
14 Brezinski, D.K., 2013, Geologic and Karst Features Map of the Hagerstown Quadrangle, Washington County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS10
15 Brezinski, D.K., and Fauth, J.L., 2009, Geologic Map of the Myersville Quadrangle and Maryland portion of the Smithsburg Quadrangle, Washington and Frederick Counties, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS11
16 Brezinski, D.K., and Fauth, J.L., 2005, Geologic Map of the Middletown Quadrangle, Frederick and Washington Counties, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS12
17 Brezinski, D.K., 2004, Geology of Part of the Point of Rocks Quadrangle, Frederick County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS13
18 Brezinski, D.K., 2021, Geology of Part of the Blue Ridge Summit Quadrangle, Frederick County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS14
19 Brezinski, D.K., 2004, Geologic Map of the Catoctin Furnace Quadrangle, Frederick County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS15
20 Brezinski, D.K., 2004, Geologic Map of the Frederick Quadrangle, Frederick County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS16
21 Brezinski, D.K., and Southworth, S., 2001, Geologic Map of the Buckeystown Quadrangle, Frederick and Montgomery Counties, Maryland. Maryland Geological Survey. Revised 2004. --- http://www.mgs.md.gov/publications/maps.html DS17
22 Brezinski, D.K., 2021, Geology of Part of the Emmitsburg and Taneytown Quadrangles, Washington and Frederick Counties, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS18
23 Brezinski, D.K., and Edwards Jr., J., 2004, Geologic Map of the Woodsboro Quadrangle, Frederick and Carroll Counties, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS19
6 Brezinski, D.B., Adams, R.K., and Connallon C.B., 2021, Geologic Map of Frederick and Washington Counties, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS2
24 Reger, J.P. and Edwards Jr., J., 2006, Geologic Map of the Union Bridge Quadrangle, Frederick and Carroll Counties, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS20
25 Reger, J.P., Brezinski, D.K., Southworth, S., and Quinn, H.A., 2004, Geologic Map of the New Windsor Quadrangle, Carroll County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS21
26 Brezinski, D.K., Southworth, S., and Edwards Jr., J., 2004, Geologic Map of the Walkersville Quadrangle, Frederick County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS22
7 Brezinski, D.K. and Conkwright, R.D. 2013. Geologic Map of Garrett, Allegany, and Western Washington Counties in Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS3
8 Southworth, S., Brezinski, D.K., Drake Jr., A.A., Burton, W.C., Orndorff, R.C., Froelich, A.J., Reddy, J.E., Denenny, D., and Daniels, D.L., 2007. Geologic Map of the Frederick 30' x 60' Quadrangle, Maryland, Virginia, and West Virginia. United States Geological Survey. --- https://pubs.er.usgs.gov/publication/sim2889 DS4
9 Brezinski, D.K., and Glaser, J.D., 2014, Geologic and Karst Features Map of the Maryland Portions of the Clear Spring and Hedgesville Quadrangles, Washington County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS5
10 Brezinski, D.K., 2013, Geologic and Karst Features Map of the Mason-Dixon Quadrangle, Washington County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS6
11 Brezinski, D.K., 2014, Geologic and Karst Features Map of the Williamsport Quadrangle, Washington County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS7
12 Brezinski, D.K., 2009, Geologic Map of Keedysville, and parts of Shepherdstown, Harpers Ferry and Charles Town Quadrangles, Washington and Frederick Counties, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS8
13 Brezinski, D.K., and Bell, S.C., 2009, Geologic Map of the Funkstown Quadrangle, Washington County, Maryland. Maryland Geological Survey. --- http://www.mgs.md.gov/publications/maps.html DS9
28 Federal Geographic Data Committee [prepared for the Federal Geographic Data Committee by the U.S. Geological Survey], 2006, FGDC Digital Cartographic Standard for Geologic Map Symbolization: Reston, Va., Federal Geographic Data Committee Document Number FGDC-STD-013-2006, 290 p., 2 plates. --- https://ngmdb.usgs.gov/fgdc_gds/geolsymstd.php FGDC-STD-013-2006

DescriptionOfMapUnits

OBJECTID MapUnit Name FullName Age Description HierarchyKey ParagraphStyle Label Symbol AreaFillRGB AreaFillPatternDescription DescriptionSourceID GeoMaterial GeoMaterialConfidence _ID
1 Qal Alluvium Alluvium Quaternary Well to poorly sorted, reddish-brown to grayish-brown mixture of unconsolidated rounded pebbles, cobbles, boulders, sand, silt and clay. These deposits form in stream channels, and on the flood plain adjacent to streams. Thickness varies from thin veneer to up to 15 feet (5 m). 01-01-01-01 DMUHeader1 --- --- 254 249 194 no pattern DS1 Alluvial sediment High DMU_1
2 Qc Colluvium Colluvium Quaternary Unsorted, light-gray to reddish-gray, angular to subangular pebbles, cobbles, boulders and sand that accumulate on slopes below outcrops, in hillslope depressions, and are present at the foot of prominent mountain ridges. Formed by the slow downslope movement of weathered material. Thickness ranges from a thin veneer to more than 100 feet (30 m). 01-01-01-02 DMUHeader1 --- --- 248 215 147 no pattern DS1 Colluvium and other widespread mass-movement sediment High DMU_2
3 Qr Residuum Residuum Quaternary Mixture of moderate reddish brown soil and rounded to angular pebbles, cobbles, and locally blocks of grayish-pink to white quartz. Thickness ranges from a veneer to 10 feet (3 m). 01-01-01-03 DMUHeader1 --- --- 242 229 78 no pattern DS1 Residual material High DMU_3
4 Qt Terrace deposits Terrace deposits Quaternary Reddish-brown to light-brown, sandy and clayey mixture of rounded pebbles to cobbles of sandstone, vein quartz, and quartzite. Locally present on elevated low relief areas above creeks and drainages. Thickness ranges from a thin veneer to more than 10 feet (3 m). 01-01-01-04 DMUHeader1 --- --- 254 234 133 no pattern DS1 Residual material High DMU_4
5 Mp Purslane Formation Purslane Formation Mississippian Light-gray, tan and reddish-brown, coarse-grained to conglomeratic, thick-bedded to cross-bedded sandstone and thin beds of gray shale and coaly shale. The Purslane is more than 300 feet (90 m) thick in western Washington County. 02-01-01-01 DMUHeader1 --- --- 204 235 255 no pattern DS1 Clastic sedimentary rock High DMU_5
6 MDr Rockwell Formation Rockwell Formation Mississippian-Devonian Interbedded, gray silty shale, light-gray to tan sandstone, and coaly and reddish shale. In Washington County, a reddish-brown to gray polymictic diamictite marks the base of the formation. The Rockwell Formation is more than 400 feet (120 m) thick in western Washington County. 02-01-01-02 DMUHeader1 --- --- 128 179 222 no pattern DS1 Sandstone and mudstone High DMU_6
7 Dh Hampshire Formation Hampshire Formation Devonian Interbedded, reddish-brown to brownish-red, locally greenish-gray sandstone, reddish-brown siltstone, shale, and rooted claystone. The thickness of the Hampshire is more than 3,000 feet (900 m) in western Washington County. 02-01-01-03 DMUHeader1 --- --- 179 179 255 no pattern DS1 Mostly sandstone High DMU_7
8 Df Foreknobs Formation Foreknobs Formation Devonian Interbedded, olive-gray medium- to coarse-grained, cross-bedded sandstone and greenish-gray to dusky-red, fossiliferous shale and siltstone. Thick (>30 feet) sandstone intervals occur near the base and near the top of the formation. The Foreknobs is more than 1,500 feet (460 m) in thickness in western Washington County. 02-01-01-04 DMUHeader1 --- --- 204 204 255 no pattern DS1 Mostly sandstone High DMU_8
9 Dhbs Harrell-Brallier-Scherr Formations (undivided) Harrell-Brallier-Scherr Formations (undivided) Devonian The Harrell Shale is a dark-gray, fissile, calcareous, thinly laminated shale that weathers to thin, yellowish-gray shale chips. The base of the Harrell is marked by the black, very fissile Burket Shale Member. The Harrell grades eastward into the Brallier Formation. The Harrell Shale is up to 150 feet thick (45 m). The Brallier Formation is a succession of thinly interbedded, gray to olive-gray shale and siltstone and thin, fine-grained sandstone. The Brallier is 2,000 to 2,500 feet thick (600 – 760 m). The Scherr Formation is interbedded reddish-brown to grayish-brown shale, thin, gray siltstone, and fine-grained, bioturbated and fossiliferous sandstone. The thickness of the Scherr is indistinct in western Washington County. 02-01-01-05 DMUHeader1 --- --- 166 179 242 no pattern DS1 Mudstone High DMU_9
10 Dm Mahantango Formation Mahantango Formation Devonian Medium-gray to olive-gray massive siltstone to fine-grained sandstone occurs near the base and top of the formation and is interbedded with siltstone, sandstone, with silty, hackly shale. Weathers brownish-gray to grayish-brown. The Mahantango Formation is approximately 1,400 feet (425 m) thick in western Washington County. 02-01-01-06 DMUHeader1 --- --- 179 204 255 no pattern DS1 Clastic sedimentary rock High DMU_10
11 Dnm Needmore-Marcellus Shales Needmore-Marcellus Shales Devonian Medium to dark brownish gray to medium dark gray, calcareous, fossiliferous shale, with thin (30 cm) beds of dark-gray, argillaceous limestone. The upper Needmore Shale consists of approximately 35 feet (10 m) of interbedded, dark-gray, argillaceous limestone and black shale. The top of the Needmore Shale is marked by the Tioga Bentonite, a brown, tuffaceous claystone. The Needmore Shale is 150 feet thick in western Washington County (45 m). The Marcellus Shale consists of black, brittle, fissile shale in the lower 100 feet (30 m), thinly interbedded black limestone and shale in the middle, and very dark gray, fissile shale containing thin (1 to 2 cm) siltstone beds at the top. The Marcellus Shale is up to 500 feet (152 m) thick. 02-01-01-07 DMUHeader1 --- --- 140 140 255 no pattern DS1 Mostly mudstone High DMU_11
12 Do Oriskany Sandstone Oriskany Sandstone Devonian Interbedded, medium- to dark-gray, siliceous shale and sandy and cherty limestone near the base (Shriver Shale Member), overlain by tan, fine-grained, calcareous sandstone, and then by light-gray, medium- to coarse-grained, thin- to thick-bedded, calcareous sandstone at the top (Ridgely Member). The Oriskany Formation is approximately 50 feet (15 m) thick in western Washington County. 02-01-01-08 DMUHeader1 --- --- 191 179 242 no pattern DS1 Mostly mudstone High DMU_12
13 DSkh Keyser-Helderberg Formations (undivided) Keyser-Helderberg Formations (undivided) Devonian-Silurian The Keyser Limestone consists of light-gray, coarsely crystalline, crinoidal limestone in the lower 50 feet (15 m), becoming medium- to dark-gray, medium- to thick-bedded, nodular, fossiliferous limestone containing dark-gray chert nodules. The upper Keyser is thin-bedded, cherty, fossiliferous limestone. The Keyser is up to 300 feet (90 m) thick in western Washington County. The Helderberg Limestone consists of medium-gray, medium-bedded, cherty, crinoidal limestone (New Creek Member), overlain in western Washington County by a light-gray, cross-bedded calcareous sandstone (Elbow Ridge Sandstone), then a medium-gray fossiliferous limestone containing beds of brown-weathering chert (Corriganville Limestone), which is succeeded by interbedded, cherty, dark-gray limestone and calcareous shale (Licking Creek Member), and topped by a thin, black, brittle shale (Mandata Shale). The Helderberg Limestone is 150 to 180 feet (30 to 55 m) thick in western Washington County. 02-01-01-09 DMUHeader1 --- --- 217 217 255 no pattern DS1 Limestone High DMU_13
14 Sto Tonoloway Formation Tonoloway Formation Silurian Medium- to light-gray, fine-grained, thinly laminated, mudcracked, dolomitic limestone with thin layers of medium-gray, fine-grained limestone, and tan laminated dolomite. The Tonoloway Limestone is approximately 400 feet thick (120 m). 02-01-01-10 DMUHeader1 --- --- 204 179 255 no pattern DS1 Limestone High DMU_14
15 Swc Wills Creek Formation Wills Creek Formation Silurian Interbedded, greenish-gray to light-gray, calcareous shale and tan, dolomitic shale containing mud cracks, laminations, and salt and gypsum casts. The thickness of the Wills Creek is approximately 400 feet (120 m). 02-01-01-11 DMUHeader1 --- --- 179 153 235 no pattern DS1 Mudstone High DMU_15
16 Sb Bloomsburg Formation Bloomsburg Formation Silurian Interbedded, reddish-gray to brownish-gray, fine-grained sandstone and hackly shale to mudrock. The Bloomsburg Formation rarely exceeds 100 feet in thickness (30 m). 02-01-01-12 DMUHeader1 --- --- 204 153 255 no pattern DS1 Mostly sandstone High DMU_16
17 Sm McKenzie Formation McKenzie Formation Silurian Interbedded, greenish-gray, calcareous shale and medium- to dark-gray, thinly bedded, fossiliferous limestone. The McKenzie Formation is up to 300 feet thick (90 m). 02-01-01-13 DMUHeader1 --- --- 230 179 235 no pattern DS1 Limestone High DMU_17
18 Sk Keefer Sandstone Keefer Sandstone Silurian Light-gray to yellowish-gray, fine- to medium-grained sandstone that weathers light-gray to yellowish-tan. The unit is thin-bedded in the lower part and thick-bedded in the middle and upper part, with lumpy and irregular bedding planes. The Keefer is moderately fossiliferous with small brachiopods, crinoid debris, and Skolithus tubes. Because it is resistant to weathering, the Keefer Formation tends to form a prominent topographic ridge. It is about 30 feet (10 m) thick at maximum thickness. 02-01-01-14 DMUHeader1 --- --- 217 199 255 no pattern DS1 Conglomerate High DMU_18
19 Srh Rose Hill Formation Rose Hill Formation Silurian Light-olive to pale reddish-gray, light-gray, greenish-gray, and deep purple shale, brownish-red sandstone, and thin reddish siltstone. The Rose Hill Formation is mostly fissile, papery shale, weathering to rusty chips. The shale is interbedded with thin, laminated, cross-bedded sandstone strata, especially in the lower portion of the formation. About 150 to 170 feet (45 to 50 m) above the base of the Rose Hill is the Cresaptown Ironstone, comprised of 20 to 30 feet (6 to 9 m) of reddish-brown, fine-grained, thin-bedded, hematitic sandstone. The Rose Hill Formation is a poorly exposed, easily weathered shale with the exception of the Cresaptown interval, which is resistant and commonly forms a topographic ridge. The thickness of the Rose Hill is estimated at 270 feet (80 m). 02-01-01-15 DMUHeader1 --- --- 235 204 255 no pattern DS1 Clastic sedimentary rock High DMU_19
20 St Tuscarora Sandstone Tuscarora Sandstone Silurian Light-gray, fine- to medium-grained, medium-bedded, dense sandstone. Locally, sandstone layers are interbedded with thin gray shale. The thickness of the Tuscarora Sandstone is less than 50 feet (15 m) in Washington County. 02-01-01-16 DMUHeader1 --- --- 242 214 242 no pattern DS1 Sandstone High DMU_20
21 Oj Juniata Formation Juniata Formation Ordovician Interbedded, reddish-brown to brownish-red, fine- to medium-grained, medium- to thick-bedded, cross-bedded sandstone and micaceous siltstone and silty shale. The Juniata Formation is estimated at 200 feet thick (60 m). 02-01-01-17 DMUHeader1 --- --- 224 112 222 no pattern DS1 Mostly sandstone High DMU_21
22 Om Martinsburg Shale Martinsburg Shale Ordovician Medium- to dark-gray, fissile shale at the base, overlain by medium-gray, silty shale and thinly interbedded medium-grained sandstone, and then by thick-bedded, medium-grained, fining upward sandstone at the top of the formation. The Martinsburg is up to 5000 feet thick in Washington County (1500 m). 02-01-01-18 DMUHeader1 --- --- 255 128 222 no pattern DS1 Clastic sedimentary rock High DMU_22
23 Omu Martinsburg Formation, upper member Martinsburg Formation, upper member Ordovician Interbedded medium-gray shale and thin, light-gray to tan, silty sandstone at the base, grading upward into interbedded greenish-gray to medium-gray siltstone and silty shale with medium- to thick-bedded medium- to coarse-grained sandstone. Thickness estimated at 2000 to 3000 feet (610 to 915 m). 02-02-01-01-01 DMUHeader1 --- --- 242 140 230 no pattern DS1 Sandstone and mudstone High DMU_23
24 Oml Martinsburg Formation, lower member Martinsburg Formation, lower member Ordovician Predominately medium- to dark-gray, silty, fissile shale with thin (<0.5 inches) siltstone interbeds. Dark-gray to black shale at base is equivalent to the Utica Shale. Thickness estimated at 1500 to 2000 feet (457 to 610 m). 02-02-01-01-02 DMUHeader1 --- --- 235 128 204 no pattern DS1 Mudstone High DMU_24
25 Oc Chambersberg Formation Chambersberg Formation Ordovician Medium- to dark-gray, nodular- to medium-bedded, fossiliferous limestone. Nodular-bedded, shaly, highly fossiliferous limestone bearing the echinoderm Echinosphaerites occurs near the base of the formation. Top of the Chambersburg Formation is marked by sharp contact with the black shales of the overlying Martinsburg. Thickness is 250 feet (76 m). 02-02-01-02 DMUHeader1 --- --- 230 179 233 no pattern DS1 Limestone High DMU_25
26 Osp St. Paul Group (undivided) St. Paul Group (undivided) Ordovician Massive, light-gray lime mudstone containing fenestral fabric at the base (Row Park Limestone), overlain by interbedded, medium- to light-gray, medium-bedded limestone and laminated dolomitic limestone at the top (New Market Limestone). The thickness of the St. Paul Group is 300 feet (91 m). 02-02-01-03 DMUHeader1 --- --- 255 166 255 no pattern DS1 Mudstone High DMU_26
27 Ops Pinesburg Station Dolomite Pinesburg Station Dolomite Ordovician Light-gray to tan, medium-bedded, highly fractured, fine-grained dolomite. Weathers to a very light gray surface. Interbedded with very light gray, laminated dolomite. Thickness is 350 to 400 feet (107 to 122 m). 02-02-01-04 DMUHeader1 --- --- 255 204 255 no pattern DS1 Dolomite High DMU_27
28 Orr Rockdale Run Formation Rockdale Run Formation Ordovician Interbedded and cyclic limestone and dolomite, cherty in the lower 400 feet (120 m). Limestone intervals consist of medium- to light-gray, ribbony and thrombolitic to stromatolitic lime mudstone to boundstone. Locally, limestone layers are light-gray oolitic grainstone. Dolomite varies from light-gray to tan, laminated to massive and fractured, with wispy dolomitic laminae. The relative proportion of the limestone to dolomite varies up section. In the lower 600 feet, limestone is typically thicker than dolomite. The progressively changes upsection so that the upper 700 feet (215 m) is dominantly dolomitic with little limestone within individual cycles. Forms very little topographic expression; many horizons are very poorly exposed. Thickness up to 2500 feet (762 m). 02-02-01-05 DMUHeader1 --- --- 235 153 214 no pattern DS1 Limestone High DMU_28
29 Osdf Dam Five Member Stonehenge Formation, Dam Five Member Ordovician Medium- to dark-gray, medium-bedded, ribbony and oolitic, lime mudstone to packstone. Near the base of the member, ribbony lime mudstone predominates. Upsection, medium-gray, ribbony lime mudstone becomes interbedded with intervals of flat-pebble lime grainstone, and hummocky, thickly laminated lime packstone and oolitic lime packstone to grainstone. Locally, thin (< 3.0 feet, 0.9 m) algal thrombolites are present. This member commonly forms a persistent and mappable ridge and is frequently well exposed. Thickness is 500 to 750 feet (150 to 215 m). 02-02-01-06-01 DMUHeader1 --- --- 255 222 255 no pattern DS1 Mostly carbonate rock High DMU_29
30 Osf Funkstown Member Stonehenge Formation, Funkstown Member Ordovician The lower part of the member is composed of massive, medium-gray, algal lime boundstone with some layers up to 7 m thick. Grading upsection into interbedded medium- to dark-gray algal thrombolites 1.5 to 2.0 m thick and medium-gray, thinly bedded to ribbony, locally fossiliferous, lime wackestone to lime packstone. Several thin, tan dolomite beds occur near the middle of the unit. Thickness: 300 to 400 feet (90 to 100 m). 02-02-01-06-02 DMUHeader1 --- --- 245 186 250 no pattern DS1 Limestone High DMU_30
31 Oss Stoufferstown Member Stonehenge Formation, Stoufferstown Member Ordovician Dark-gray, argillaceous, thinly bedded to ribbony, lime mudstone with thin beds of flat-pebble lime grainstone conglomerate and hummocky, discontinuous, laminated limestone. A single, 10-foot (3 m) interval of massive, dark-gray, thrombolitic, algal boundstone occurs approximately 30 feet (10 m) above the base of the member. This member weathers into thin brown and orange chips, which litter overlying soil. Forms a low, discontinuous ridge. Thickness varies from 230 to 295 feet (70 to 90 m). 02-02-01-06-03 DMUHeader1 --- --- 235 128 235 no pattern DS1 Mostly carbonate rock High DMU_31
32 Ccsg Shady Grove Member Conococheague Formation, Shady Grove Member Cambrian Interbedded, medium- to light-gray, ribbony lime mudstone that weathers to flaggy to platy beds, and arenaceous grainstones exhibiting edgewise and flat-pebble conglomerates. Locally, thin pastel blue and pink marble strata are developed. Black or gray chert fragments and brown-weathering quartz sandstone cobbles are frequently abundant in overlying soil. Thickness is 650 to 750 feet (200 to 230 m). 02-02-01-07-01 DMUHeader1 --- --- 255 217 230 no pattern DS1 Mostly mudstone High DMU_32
33 Ccz Zullinger Member Conococheague Formation, Zullinger Member Cambrian Predominantly cyclically bedded, medium- to dark-gray, thrombolitic limestone and gray, ribbony and laminated limestone and tan, laminated dolomite. Thrombolites range in thickness from 3 to 6 feet (1 to 2 m) within thrombolitic intervals to less than 1 foot (0.3 m) within the ribbony intervals. Several dark-gray, oolitic intervals are present in the upper part of this member. Thickness is 1500 to 1800 feet (460 to 550 meters). 02-02-01-07-02 DMUHeader1 --- --- 255 191 217 no pattern DS1 Limestone High DMU_33
34 Ccb Big Spring Station Member Conococheague Formation, Big Spring Station Member Cambrian Tan, massive dolomite interbedded with tan to light-gray, laminated dolomite; unit characterized by dark-brown weathering. At the type section on the western side of the Hagerstown Valley, this member is characterized by interbeds of light-gray, cross-bedded, calcareous, intraclastic, quartzarenitic sandstone approximately 3 feet (1 m) in thickness. Member becomes interbedded with gray, dolomitic thrombolite beds near the top. Thickness ranges from 200 to 300 feet (60 to 90 m). 02-02-01-07-03 DMUHeader1 --- --- 255 166 204 no pattern DS1 Dolomite High DMU_34
35 Ce Elbrook Formation Elbrook Formation Cambrian Lower part of the formation is very poorly exposed and contains interbedded tan, thin- to thick-bedded limestone and dolomite, which frequently weather shaly and are intercalated with medium-bedded, dark-gray limestone. Middle part of the formation contains cyclic, dark-gray limestone and dolomitic limestone. The upper part of the formation, and making up its greatest thickness, is cyclically bedded, gray, thrombolitic limestone and ribbony to laminated limestone and dolomite. Thickness ranges from 2200 to 2500 feet (670 to 760 m). 02-02-01-08 DMUHeader1 --- --- 255 153 179 no pattern DS1 Limestone High DMU_35
36 Cwac Chewsville Member Waynesboro Formation, Chewsville Member Cambrian Reddish-brown to chocolate-brown, silty shale, siltstone, and silty fine-grained sandstone, interbedded with white, calcareous, Skolithus-burrowed sandstone beds (2 to 6 cm thick) and tan to buff, medium-bedded, sandy dolostone. This unit usually is the most diagnostic of the Waynesboro lithologies and typically forms a ridge, which makes it easily traceable. Thickness estimated at 90 to 125 feet (30 to 45 m). 02-02-01-09-01 DMUHeader1 --- --- 255 171 222 no pattern DS1 Clastic sedimentary rock High DMU_36
37 Cwak Cavetown Member Waynesboro Formation, Cavetown Member Cambrian Medium- to thick-bedded, medium- to coarse-grained, intraclastic grainstone; tan, laminated dolostone and dolomitic limestone; and medium-gray, oolitic, lime grainstone, ribbony carbonates, and burrowed-mottled dolomitic limestone. This unit is typically poorly exposed, but makes up the greatest thickness of the formation. Thickness estimated at 600 to 750 feet (200 to 250 m). 02-02-01-09-02 DMUHeader1 --- --- 255 133 207 no pattern DS1 Dolomite High DMU_37
38 Cwar Red Run Member Waynesboro Formation, Red Run Member Cambrian Interbedded, tan-weathering, punky, fine-grained sandstones; green-gray shale; gray sandy limestone; and laminated dolostone. Locally thin (0.6 to 5 cm) layers of red siltstone and sandstone are present. Typically, this unit forms a low ridge somewhat lower in height than the Chewsville Member. Thickness estimated at 150 to 225 feet (60 to 75 m). 02-02-01-09-03 DMUHeader1 --- --- 255 110 163 no pattern DS1 Mostly sandstone High DMU_38
39 Ct Tomstown Formation Tomstown Formation Cambrian Predominantly buff-weathering, medium- to dark-gray dolomite, dolomitic limestone, and limestone. Divided into 4 members. Total thickness is 1,200 to 1,300 feet (366 to 396 m). 02-02-01-10 DMUHeader1 --- --- 204 128 153 no pattern DS1 Dolomite High DMU_39
40 Ctd Dargan Member Tomstown Formation, Dargan Member Cambrian Interbedded and cyclical dolomite and limestone. Cycles consist of alternations of dark-gray, bioturbated dolomite and medium- to dark-gray, laminated dolomite, or dark-gray dolomite or limestone and tan, laminated, silty dolomite. Cycles of thin-bedded limestone and tan dolomite are more prevalent near the top of the member. Thickness is approximately 700 feet (215 m). 02-02-01-10-01 DMUHeader1 --- --- 252 204 179 no pattern DS1 Dolomite High DMU_40
41 Ctb Benevola Member Tomstown Formation, Benevola Member Cambrian Light-gray to white, massive to poorly bedded, highly fractured, sugary dolomite. The Benevola Member varies from white to very light gray, on both fresh and weathered surfaces. Bedding is rarely evident, except within polished slabs where faint ghosts of crossbedding are common. Thickness is 100 to 150 feet (33 to 50 m). 02-02-01-10-02 DMUHeader1 --- --- 242 158 179 no pattern DS1 Dolomite High DMU_41
42 Ctf Fort Duncan Member Tomstown Formation, Fort Duncan Member Cambrian Medium- to dark-gray, thick-bedded, mottled dolomite with white, void-filling, sparry dolomite. Weathered surface characterized by irregular, clotted to anastomosing network of algae. Layers of the white, sparry dolomite, 0.5 to 1.5 inches wide, fill voids that are continuous in beds for up to several yards (several meters) and contrasts the darker mottled dolomite. Thickness ranges from 200 to 250 feet (60 to 75 m). 02-02-01-10-03 DMUHeader1 --- --- 217 102 128 no pattern DS1 Dolomite High DMU_42
43 Ctbh Bolivar Heights Member Tomstown Formation, Bolivar Heights Member Cambrian The Bolivar Heights Member is characterized by three stratigraphically stacked lithologies. The basal lithology is a tan, vuggy dolomite that is in contact with the underlying Antietam Formation. This dolomite ranges from 10 to 40 feet (9 to 12 m) in thickness, and is rarely exposed. Overlying the tan basal dolomite is an interval 40 to 50 feet (12 to 15 m) thick, comprised of very light gray, sheared, laminated, dolomitic marble (Keedysville marble bed). Above the Keedysville marble bed, the Bolivar Heights Member consists of about 200 feet (60 m) of thin- to medium-bedded, dark-gray, ribbony, burrow-mottled, lime mudstone that weathers light-gray in color. The number and density of burrows vary among beds, with very little burrowing in some layers and an anastomosing network of burrows in others. Thickness is 200 to 250 feet (60 to 75 m). 02-02-01-10-04 DMUHeader1 --- --- 255 191 166 no pattern DS1 Dolomite High DMU_43
44 Ca Antietam Formation Antietam Formation Cambrian The lower part of the formation is greenish-gray, highly cleaved, slaty, phyllitic shale and siltstone interbedded with white, Skolithos-burrowed, and fine-grained sandstone. These lower strata grade upsection into medium-bedded, white, bioturbated and crossbedded, fine- to medium-grained sandstone in the middle of the formation. The uppermost strata of the formation consist of light- to medium-gray, crossbedded, vuggy, coarse-grained granular sandstone to conglomerate. Thickness ranges from 500 to 800 feet (150 to 245 m). 03-01-01-01 DMUHeader1 --- --- 235 128 153 no pattern DS1 Sandstone and mudstone High DMU_44
45 Ch Harpers Formation Harpers Formation Cambrian Brownish-gray to dark greenish gray, silty phyllitic shale to highly sheared phyllitic siltstone with intervals of brownish-gray, medium-grained, silty sandstone. On Catoctin Mountain: light brownish gray to light olive gray, sheared, muscovite(?)-sericite phyllite weathering to pale red, moderate reddish brown, and yellowish-brown. Approximate formation thickness 1,000 to 1,500 feet (300 to 450 m). On South Mountain: Primarily light olive gray and dark greenish gray, highly cleaved phyllitic siltstone. Interbeds of medium-grained, medium-gray sandstone and quartzite occur locally. Estimated formation thickness greater than 2500 feet (760 m). 03-01-01-02 DMUHeader1 --- --- 247 196 222 no pattern DS1 Clastic sedimentary rock High DMU_45
46 Chm Harpers Formation, metasandstone Harpers Formation, metasandstone Cambrian Commonly thin (1 inch to 16 feet; 3 cm to 5 m), dark green gray, fine to medium-grained, highly argillaceous metasandstones containing Skolithus burrows, especially near the top of the formation. Mappable metasandstone intervals are up to 30 feet (10 m) thick. 03-01-01-02-01 DMUHeader1 --- --- 217 110 159 no pattern DS1 Metasedimentary rock High DMU_46
47 Chma Mont Alto Member Harpers Formation, Mont Alto Member Cambrian Light-to medium-gray, coarse grained to conglomeratic, crossbedded quartzite, commonly less than 30 feet (10 m) in thickness. 03-01-01-02-02 DMUHeader1 --- --- 255 176 231 no pattern DS1 Quartzite High DMU_47
48 Cwo Owens Creek Member Weverton Formation, Owens Creek Member Cambrian Dark to very dark gray, very coarse grained to conglomeratic, crossbedded graywacke. Although commonly crossbedded, the very coarse grained nature of this unit makes recognition of crossbedding difficult. Large (1 to 3 cm) white and pink quartz pebbles are characteristic of this member, although they are only locally common. Thickness ranges from 150 to 180 feet (50 to 60 m). 03-01-01-03-01 DMUHeader1 --- --- 212 120 120 no pattern DS1 Metasedimentary rock High DMU_48
49 Cwm Maryland Heights Member Weverton Formation, Maryland Heights Member Cambrian Thin (less than 33 feet; 10 m), medium- to dark-gray quartzite and graywacke interbedded with very dark gray, highly cleaved siltstone and phyllitic shale. Shales and siltstones are very poorly exposed and individual quartzites and graywackes are only locally traceable. Thickness ranges from 150 to 350 feet (50 to 115 m). 03-01-01-03-02 DMUHeader1 --- --- 247 153 153 no pattern DS1 Metasedimentary rock High DMU_49
51 Cwb Buzzard Knob Member Weverton Formation, Buzzard Knob Member Cambrian Light-gray to medium-gray, medium-bedded quartzite with dark-gray, argillaceous layers up to 4 cm thick separating the quartzite beds. Crossbedding within individual quartzite strata is pervasive. The Buzzard Knob Member has an estimated thickness of 50 to 150 feet (15 to 45 m). 03-01-01-03-03 DMUHeader1 --- --- 255 222 209 no pattern DS1 Quartzite High DMU_51
52 CZl Loudoun Formation Loudoun Formation Late Proterozoic? Cambrian? Medium- to dark-gray, medium-bedded conglomerate and black, tuffaceous phyllite. Lithology is very variable, ranging from a crossbedded quartz-pebble conglomerate to a highly cleaved polymictic conglomerate with a matrix of flattened phyllite pebbles. The localized distribution and rapid thickness variations of this formation may be the result of the original deposition patterns. The Loudoun Formation ranges in thickness from 30 to 200 feet (9 to 60 m). 03-01-01-04 DMUHeader1 --- --- 240 179 179 no pattern DS1 Clastic sedimentary rock High DMU_52
53 CZlc Loudoun Formation, conglomerate Loudoun Formation, conglomerate Late Proterozoic? Cambrian? Medium-bedded, medium light gray, grayish yellow green or dusky blue conglomerate that weathers light-gray and greenish-gray or dusky blue. Contains oval pebbles of quartz, quartzite, rhyolite, and granite(?) that are 0.5 to 4.0 cm long, and flattened, dark-colored phyllite fragments, 1.5 to 3.0 cm long; matrix is a medium- to coarse-grained graywacke. Conglomerate beds are intercalated with cross-laminated, thin- to medium-bedded, medium- to coarse-grained, pebbly graywacke and thin intervals of very dusky purple, dusky blue, or very dusky red phyllites and quartz phyllites. Unit grades upward into pebbly quartzites. Conglomerate member ranges from 0 to 50 feet (0 to 15 m) in thickness. 03-01-01-04-01 DMUHeader1 --- --- 219 168 168 no pattern DS1 Conglomerate High DMU_53
54 Zcr Catoctin Formation, metarhyolite Catoctin Formation, metarhyolite Late Proterozoic Undifferentiated bluish-gray metarhyolite in which no single variety is dominant. 03-01-01-05-01 DMUHeader1 --- --- 193 135 77 no pattern DS1 Meta-felsic and intermediate rock High DMU_54
55 Zcra Catoctin Formation, aphanitic metarhyolite Catoctin Formation, aphanitic metarhyolite Late Proterozoic Aphanitic, bluish-gray metarhyolite that is massive and dense, and exhibits a conchoidal fracture. Rare phenocrysts, where present, comprise less than 1 percent of the rock. Weathers bone white to very light gray. 03-01-01-05-02 DMUHeader1 --- --- 232 219 204 no pattern DS1 Meta-felsic and intermediate rock High DMU_55
56 Zcrb Catoctin Formation, metarhyolite breccia Catoctin Formation, metarhyolite breccia Late Proterozoic Dusky blue-gray, metarhyolite breccia with angular to subrounded clasts that weather to a lighter color than the felsic matrix. 03-01-01-05-03 DMUHeader1 --- --- 143 110 89 no pattern DS1 Meta-felsic and intermediate rock High DMU_56
57 Zcrf Catoctin Formation, flow banded metarhyolite Catoctin Formation, flow banded metarhyolite Late Proterozoic Flow-banded, bluish-gray metarhyolite containing nearly planar, locally convoluted flow bands 0.12 to 0.4 inch (3 to 10 mm) thick. Laminae are discontinuous and most prominent on weathered surfaces. Phenocrysts constitute less than 2 percent of the rock. 03-01-01-05-04 DMUHeader1 --- --- 191 138 102 no pattern DS1 Meta-felsic and intermediate rock High DMU_57
58 Zcrp Catoctin Formation, porphyritic metarhyolite Catoctin Formation, porphyritic metarhyolite Late Proterozoic Porphyritic, bluish-gray metarhyolite with conspicuous very light gray to very pale orange or pinkish-gray feldspar laths. Phenocrysts are up to 0.2 inches (6 mm) long and make up 2 to 5 percent of the rock. 03-01-01-05-05 DMUHeader1 --- --- 179 130 110 no pattern DS1 Meta-felsic and intermediate rock High DMU_58
59 Zcrr Catoctin Formation, red metarhyolite Catoctin Formation, red metarhyolite Late Proterozoic Grayish-red to dusky reddish purple, porphyritic metarhyolite. Phenocrysts make up 3 to 5 percent of the rock and are predominately euhedral, pink to light-gray feldspar and reddish quartz. Estimated thickness 200 to 300 feet (20 to 90 m). 03-01-01-05-06 DMUHeader1 --- --- 204 150 128 no pattern DS1 Meta-felsic and intermediate rock High DMU_59
60 Zcdf Catoctin Formation, felsic dikes Catoctin Formation, felsic dikes Late Proterozoic Massive, light-gray to medium-gray felsite; weathers light orange brown. Contains very few small feldspar phenocrysts. 03-01-01-05-07 DMUHeader1 --- --- 242 89 140 no pattern DS1 Fine-grained, felsic-composition intrusive igneous rock High DMU_60
61 Zcm Catoctin Formation, metabasalt Catoctin Formation, metabasalt Late Proterozoic Medium to dark greenish gray, chloritic, locally amygdaloidal, epidote-rich metabasalt. Some areas are composed of highly sheared chlorite schist. Epidote occurs as light-green veins and nodules. Thickness estimated at greater than 1000 feet by Fauth (1977). 03-01-01-05-08 DMUHeader1 --- --- 222 204 179 no pattern DS1 Meta-mafic rock High DMU_61
62 Zcmp Catoctin Formation, porphyritic metabasalt Catoctin Formation, porphyritic metabasalt Late Proterozoic Greenish-gray to bluish-green rock that weathers bluish-gray to dark greenish gray. Very prominent white to very light gray, randomly oriented lath-shaped feldspar (albite?) phenocrysts. Individual crystals or aggregates may range in length from 1 to 25 mm and make up about 2 to 7 percent of the rock. 03-01-01-05-09 DMUHeader1 --- --- 186 153 128 no pattern DS1 Meta-mafic rock High DMU_62
63 Zcp Catoctin Formation, phyllite Catoctin Formation, phyllite Late Proterozoic Light-to medium-gray phyllite containing highly elongated light-gray flecks and blebs. Thickness of this unit appears to be less than 100 feet. 03-01-01-05-10 DMUHeader1 --- --- 204 179 128 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_63
64 Zcp1 Catoctin Formation, phyllite unit 1 Catoctin Formation, phyllite unit 1 Late Proterozoic Poorly exposed, lustrous, light-gray to medium dark gray, olive-gray phyllite, or mottled yellowish-gray and medium-gray phyllite. Commonly contain numerous light-colored, flattened and elongate blebs from 1x10 to 10x20 mm in size. Unit thickness is estimated to be between 50 and 100 feet (15 to 30 m). 03-01-01-05-11 DMUHeader1 --- --- 153 128 89 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_64
65 Zcp2 Catoctin Formation, phyllite unit 2 Catoctin Formation, phyllite unit 2 Late Proterozoic Light greenish gray, moderate greenish gray and very light gray streaked phyllite; may be silicified. Weathered surfaces commonly soft and soapy. Lithologically similar to parts of the lavender phyllite exposed in adjacent parts of the Myersville 7.5-minute quadrangle (Fauth, 1977). Estimated thickness between 30 and 50 feet (9 and 15 m). 03-01-01-05-12 DMUHeader1 --- --- 214 201 158 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_65
66 Zcp3 Catoctin Formation, phyllite unit 3 Catoctin Formation, phyllite unit 3 Late Proterozoic Medium dark gray, medium bluish gray, or light-gray phyllite containing blebs 2 to 4 mm long. Weathers to light-colored, flat or platy fragments up to 15x40 cm in size. Estimated thickness between 30 and 60 feet (9 and 15 m). 03-01-01-05-13 DMUHeader1 --- --- 191 166 128 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_66
67 Zcpl Catoctin Formation, lavender phyllite Catoctin Formation, lavender phyllite Late Proterozoic Pale purple to grayish red-purple or very light gray phyllite. Locally, color is mottled with red quartz grains and light-gray to yellowish-gray porphyroblasts of feldspar. Estimated thickness of 30 to 50 feet (9 to 15 m). 03-01-01-05-14 DMUHeader1 --- --- 217 196 184 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_67
68 Zcb Catoctin Formation, basaltic dike Catoctin Formation, basaltic dike Late Proterozoic Dark greenish gray, locally phyllitic and chloritic basalt. Commonly has strongly developed cleavage. These bodies are present in the basement gneiss complex and appear to represent dikes that once contacted the main Catoctin outcrop belt. 03-01-01-05-15 DMUHeader1 --- --- 204 179 179 no pattern DS1 Extrusive igneous material High DMU_68
69 Zcd Catoctin Formation, mafic dikes Catoctin Formation, mafic dikes Late Proterozoic Typically dark greenish gray to grayish olive green, fine- to medium-grained metadiabase or metabasalt. Commonly occurs as dikes and sills(?) intruding rocks of basement gneiss complex. Crosscutting relationships with older, gneissic structure discernible in several outcrops. Dikes range in width from several inches up to 40 feet (12 m). Thicker dikes may show chilled margins; thinner dikes usually have been altered to chlorite phyllite or schist. Individual dikes may be traceable and mappable for distances ranging from a few hundred to thousands of feet (about 100 m to more than 1000 m). 03-01-01-05-16 DMUHeader1 --- --- 191 77 115 no pattern DS1 Meta-mafic rock High DMU_69
70 Zsr Swift Run Formation Swift Run Formation Late Proterozoic Medium gray brown, silty sandstone with intervals of very light gray, foliated, micaceous marble. Marble locally quarried for agricultural purposes. Thickness estimated at 0 to 200 feet (0 to 60 m). 03-01-01-06 DMUHeader1 --- --- 204 128 179 no pattern DS1 Meta-carbonate rock High DMU_70
71 Zsrp Swift Run Formation, phyllite Swift Run Formation, phyllite Late Proterozoic Very light gray, dusky yellow green and very light greenish gray, lustrous quartz sericite(?) phyllite that weathers grayish-orange to very light gray. Quartz occurs as medium to coarse detrital grains either uniformly disseminated throughout the rock or concentrated in thin bands or lenses. Estimated thickness ranges from 0 to 75 feet (0 to 23 m). 03-01-01-06-01 DMUHeader1 --- --- 217 166 191 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_71
72 Zsrq Swift Run Formation, quartzite Swift Run Formation, quartzite Late Proterozoic Very light gray, thin-bedded, laminated and cross-laminated sericitic quartzite that weathers light greenish gray to light-gray; and medium light gray, thick-bedded, coarse-grained, laminated quartzite, weathering light-gray. Locally, a white to very light gray, graded, fine- to coarse-grained, friable feldspathic sandstone that weathers yellowish-gray and grayish-orange. Estimated thickness ranges from 0 to 90 feet (0 to 27 m). 03-01-01-06-02 DMUHeader1 --- --- 236 206 218 no pattern DS1 Quartzite High DMU_72
73 Ygl Basement gneiss complex, leucocratic gneiss Basement gneiss complex, leucocratic gneiss Middle Proterozoic Fine- to medium-grained, tan to very light gray, massive, finely banded to indistinctly foliated chlorite-quartz-microcline-plagioclase gneiss. Very light gray to yellowish-gray granitic rock weathers very pale orange, grayish-pink, and grayish-orange to pale brown. 03-01-01-07-01 DMUHeader1 --- --- 161 189 138 no pattern DS1 Medium and high-grade regional metamorphic rock, of unspecified origin High DMU_73
74 Ygt Basement gneiss complex, garnet gneiss Basement gneiss complex, garnet gneiss Middle Proterozoic Fine- to medium-grained, very light gray, finely banded to indistinctly foliated quartz-microcline-plagioclase gneiss. Similar to leucocratic gneiss, but with scattered garnets. Weathers light-gray to yellowish. 03-01-01-07-02 DMUHeader1 --- --- 199 215 158 no pattern DS1 Schist and gneiss, of sedimentary-rock origin High DMU_74
75 Ygb Basement gneiss complex, biotite gneiss Basement gneiss complex, biotite gneiss Middle Proterozoic Fine- to medium-grained, very light gray to yellowish-gray granitic rock that weathers very pale orange, grayish-pink, and grayish-orange to pale brown. Usually massive, but a faint foliation is commonly discernible. Quartz occurs in prominent grayish-blue grains. Biotite, the principal varietal mineral, is brownish-black to greenish-black. In places, the gneiss is interlayered with thin, irregular bands or zones of biotite schist. 03-01-01-07-03 DMUHeader1 --- --- 179 204 128 no pattern DS1 Fine-grained, felsic-composition intrusive igneous rock High DMU_75
76 Ygh Basement gneiss complex, hornblende gneiss Basement gneiss complex, hornblende gneiss Middle Proterozoic Medium-grained, granular, massive or poorly foliated biotite-hornblende-plagioclase gneiss that weathers light olive gray, pale olive, or greenish-gray. May contain prominent greenish-black hornblende porphyroblasts 5 to 10 mm long. Hornblende, grayish-black biotite, and dusky green to dusky yellow green chlorite contrast with very light gray to light greenish gray plagioclase feldspar. 03-01-01-07-04 DMUHeader1 --- --- 204 204 153 no pattern DS1 Medium and high-grade regional metamorphic rock, of unspecified origin High DMU_76
77 Ygp Basement gneiss complex, paragneiss Basement gneiss complex, paragneiss Middle Proterozoic Fine- to medium-grained, tan to rusty red, highly foliated micaceous-quartz-garnet paragneiss to schist. Weathers to a yellowish-brown or very pale orange, schistose rock. 03-01-01-07-05 DMUHeader1 --- --- 204 235 153 no pattern DS1 Medium and high-grade regional metamorphic rock, of unspecified origin High DMU_77
78 Jd Jurassic Dikes Jurassic Dikes Jurassic Medium- to dark-gray, medium- to fine-grained diabase, weathering to rusty orange-brown spheroidal boulders and cobbles. Diabase dike(s) range in thickness from 3 to 15 feet (1 to 5 m). 04-01-01-01 DMUHeader1 --- --- 255 77 0 no pattern DS1 Fine-grained, intermediate-composition intrusive igneous rock High DMU_78
79 JTrtm Thermally metamorphosed rocks Thermally metamorphosed rocks Triassic Medium- to olive-gray, hard, brittle, and fractured hornfels and meta-arkose, adjacent to diabase intrusions. Includes dark-gray to olive-black hornfels in contact metamorphic zones that are a few feet wide adjacent to narrow dikes but may be hundreds of feet thick adjacent to thick sills. 04-01-01-02 DMUHeader1 --- --- 140 167 189 no pattern DS1 Contact-metamorphic rock High DMU_79
80 Trg Gettysburg Formation Gettysburg Formation Triassic Reddish-brown to reddish-gray, locally greenish-gray, medium-grained siltstone, claystone, mudstone, and fine-grained sandstone. Sandstone beds exhibit sharp bases, shale pebble-lag conglomerates, and fining upward character. Claystone intervals are thoroughly root-mottled and contain light-gray caliche nodules. Thickness is estimated at up to 8000 feet (2440 m). 04-02-01-01 DMUHeader1 --- --- 158 209 209 no pattern DS1 Clastic sedimentary rock High DMU_80
81 Trgc Gettysburg Formation, conglomerate Gettysburg Formation, conglomerate Triassic Limestone conglomerate marks the western edge of the Gettysburg Basin in Maryland and is similar in appearance and position to the Leesburg Formation in the Culpeper Basin. Thickness is in question, but may be as much as 2438 m (8000 feet). 04-02-01-01-01 DMUHeader1 --- --- 194 232 232 no pattern DS1 Conglomerate High DMU_81
82 Trgh Heidlersburg Member Gettysburg Formation, Heidlersburg Member Triassic Interbedded gray calcareous siltstone and shale; laminated, mudcracked, and brecciated limestone; and dark grayish brown to reddish-brown siltstone and shale. Bedding is defined by cycles of gray siltstone and shale grading upward into gray, laminated limestone followed by reddish siltstone. The Heidlersburg Member is 400 to 500 feet thick in the Maryland part of Emmitsburg Quadrangle. 04-02-01-01-02 DMUHeader1 --- --- 27 183 222 no pattern DS1 Mostly mudstone High DMU_82
83 Trn New Oxford Formation New Oxford Formation Triassic Brownish-red to dark reddish brown, argillaceous to silty sandstone and micaceous siltstone with subordinate interbedded silty shale and mudstone. Some reddish-gray to gray arkosic sandstone also occurs. Claystone intervals are thoroughly root-mottled and contain light-gray caliche nodules. Throughout the region, the siltstone-shale-arkose unit overlies a basal quartz-pebble conglomerate. The formation may be as thick as 10,000 feet (3048 m). 04-02-01-02 DMUHeader1 --- --- 153 245 240 no pattern DS1 Sandstone and mudstone High DMU_83
84 Trns New Oxford Formation, sandstone New Oxford Formation, sandstone Triassic Interbedded, light reddish gray to reddish-brown sandstone. Sandstones exhibit sharp bases with shale-pebble lag conglomerates, and fining upward character. 04-02-01-02-01 DMUHeader1 --- --- 128 235 224 no pattern DS1 Sandstone High DMU_84
85 Trni Irishtown Member New Oxford Formation, Irishtown Member Triassic Light reddish gray, subangular to subrounded, quartz and limestone conglomerate. Clasts are predominately gray limestone, tan dolostone, or quartz pebbles with a matrix of reddish-brown, calcareous mudstone. Poorly exposed, and thickness is in question (Brezinski, 2004). 04-02-01-02-02 DMUHeader1 --- --- 102 207 204 no pattern DS1 Conglomerate High DMU_85
86 Trl Leesburg Formation Leesburg Formation Triassic Light-gray to light reddish gray, very thickly bedded, boulder conglomerate. Clasts are mainly subangular to subrounded limestone and dolostone of Cambrian and Ordovician age, but locally Triassic age siltstone and sandstone are prevalent. Thickness ranges from 100 to 3000 feet (30 to 910 m). 04-02-02-01 DMUHeader1 --- --- 102 191 204 no pattern DS1 Conglomerate High DMU_86
87 Trb Balls Bluff Siltstone Balls Bluff Siltstone Triassic Brownish-red to reddish-brown, argillaceous, massive siltstone with thin fine-grained sandstone interbeds. Thickness is estimated at 200 to 4500 feet (61 to 1372 m). 04-02-02-02 DMUHeader1 --- --- 140 217 230 no pattern DS1 Sandstone and mudstone High DMU_87
88 Trmp Poolesville Member Manassas Formation, Poolesville Member Triassic Reddish-brown to reddish-gray, locally greenish-gray, medium-grained sandstone and reddish, variegated claystone. Sandstone beds exhibit sharp, convex-down bases, shale-pebble lag conglomerates, and fining-upward character. Claystone intervals are thoroughly root mottled and contain light-gray caliche carbonate nodules. The thickness of this member is estimated at 500 to 3000 feet (152 to 914 m). 04-02-02-03-01 DMUHeader1 --- --- 166 204 230 no pattern DS1 Sandstone and mudstone High DMU_88
89 Trmps Poolesville Member, sandstone beds Manassas Formation, Poolesville Member, sandstone beds Triassic Medium-grained sandstone beds exhibiting sharp, convex-down bases, shale-pebble lag conglomerates and fining upward character. 04-02-02-03-01-01 DMUHeader1 --- --- 102 166 204 no pattern DS1 Sandstone High DMU_89
90 Trmt Tuscarora Creek Member Manassas Formation, Tuscarora Creek Member Triassic Light-gray to light reddish gray, subangular to subrounded, limestone and dolomite conglomerate. Clasts are predominately tan dolostone, but locally reddish siltstone, sandstone, and some limestone clasts are prevalent. Matrix is a reddish-brown calcareous mudstone to reddish clayey carbonate. Thickness ranges from a feather edge to 100 feet (30 m). 04-02-02-03-02 DMUHeader1 --- --- 189 219 235 no pattern DS1 Carbonate rock High DMU_90
91 Ogw Woodsboro Member Grove Formation, Woodsboro Member Ordovician Thin-bedded, dark-gray, fine-grained limestone interbedded with medium-bedded, bioturbated, dark-gray, fine-grained limestone, and thin, wavy bedded limestone with tan, dolomitic partings. Top of Woodsboro Member not exposed because it is covered by the Triassic New Oxford Formation. Thickness is 500 feet (152 m). 04-02-03-01-01 DMUHeader1 --- --- 255 204 255 no pattern DS1 Limestone High DMU_91
92 Ogf Fountain Rock Member Grove Formation, Fountain Rock Member Ordovician Very thickly bedded, medium light gray, locally sandy, thrombolitic and stromatolitic algal limestone and medium-gray, laminated dolomitic limestone and olive-gray dolomite. Thickness is in question, but may range from 1000 to 3300 feet (305 m to 1006 m) in central Frederick County. 04-02-03-01-02 DMUHeader1 --- --- 255 179 255 no pattern DS1 Limestone High DMU_92
93 Ogfs Fountain Rock Member, sandstone Grove Formation, Fountain Rock Member, sandstone Ordovician Two cross-bedded sandstone units recognized in the middle of the formation were identified and traced. 04-02-03-01-02-01 DMUHeader1 --- --- 255 153 255 no pattern DS1 Sandstone High DMU_93
94 Ogc Ceresville Member Grove Formation, Ceresville Member Ordovician Medium light gray to medium-gray, thick-bedded and cross-bedded, arenaceous limestone and sandy, dolomitic limestone with thin interbeds (1 ft or 0.3 m) of medium light gray, sandy, thrombolitic dolomite. Thickness is approximately 150 to 200 feet (46 to 61 m). 04-02-03-01-03 DMUHeader1 --- --- 255 128 255 no pattern DS1 Limestone High DMU_94
95 Cfu Frederick Formation, undivided Frederick Formation, undivided Cambrian Medium- to dark-gray, thin- to medium-bedded, pyritic, argillaceous limestone and shaly limestone. Contains intervals of tan-weathering dolomitic shale and sandy brecciated limestone. In the Emmitsburg Quadrangle, the Frederick Formation is highly sheared and highly deformed. Thickness in the Emmitsburg Quadrangle is estimated at 500 to 1000 feet (50 to 305 m). 04-02-03-02 DMUHeader1 --- --- 255 145 114 no pattern DS1 Limestone High DMU_95
97 Cfl Lime Kiln Member Frederick Formation, Lime Kiln Member Cambrian Interbedded, thinly laminated to thinly bedded, dark-gray, fine-grained limestone, calcareous shale, and medium-bedded, fine-grained limestone near the base, becoming more thickly interbedded toward the top with medium dark gray, fine-grained limestone with wavy bedding and stromatolitic algal beds. Near the top, the member becomes interbedded with cross-bedded, sandy, medium light gray limestone. Thickness is 700 feet (213 m). 04-02-03-02-01 DMUHeader1 --- --- 240 153 166 no pattern DS1 Limestone High DMU_97
96 Cfa Adamstown Member Frederick Formation, Adamstown Member Cambrian Thinly interbedded, medium dark gray to dark-gray, argillaceous, fine-grained limestone and dusky yellow to medium dark gray, silty dolomite. Limestone beds range from 0.1 to 2.0 inches (0.3 to 5.1 cm) in thickness. Several thin (6.0 to 30 feet or 1.8 to 9.1 m), dark greenish gray to greenish-black, light olive brown weathering, silty, calcareous shale intervals are present throughout the member. The top of the member is mapped at the base of the lowest medium to thick bed of sandy or algal limestone. Thickness is approximated at 1000 feet (305 m). 04-02-03-02-02 DMUHeader1 --- --- 255 204 204 no pattern DS1 Limestone High DMU_96
98 Cfr Rocky Springs Station Member Frederick Formation, Rocky Springs Station Member Cambrian Interbedded dark-gray, thinly bedded, lime mudstone and black dolomitic shale, massive, medium-gray polymictic breccias, medium-gray sandy limestone, and dark-gray, flaggy lime mudstone. Top of the member is mapped at the top of the stratigraphically highest polymictic breccia or sandstone interval. Thickness is approximated at 1200 feet (425 m) on the eastern flank, but is likely much thicker on the western flank. 04-02-03-02-03 DMUHeader1 --- --- 255 166 140 no pattern DS1 Clastic sedimentary rock High DMU_98
99 Cfrb Rocky Springs Station Member, breccia Frederick Formation, Rocky Springs Station Member, breccia Cambrian Massive, medium-gray, polymictic breccias on the western flank of the synclinorium but are not evident on the east flank. 04-02-03-02-03-01 DMUHeader1 --- --- 255 120 120 no pattern DS1 Clastic sedimentary rock High DMU_99
101 Cfms Monocacy Member, shale bed Frederick Formation, Monocacy Member, shale bed Cambrian Black shale that marks the top of the Monocacy Member and is more than 50 feet (15 m) thick. 04-02-03-02-04-01 DMUHeader1 --- --- 255 179 128 no pattern DS1 Clastic sedimentary rock High DMU_101
100 Cfm Monocacy Member Frederick Formation, Monocacy Member Cambrian Thickly interbedded, black, platy shale, rubbly, dolomitic breccia, laminated lime mudstone, and black shale. A laterally continuous black shale marks the top of the member. Thickness of this member is approximately 200 feet (61 m). 04-02-03-02-04-02 DMUHeader1 --- --- 255 143 133 no pattern DS1 Clastic sedimentary rock High DMU_100
102 Car Araby Formation Araby Formation Cambrian Thickly bedded, greenish-black to grayish-black, very fine grained to fine-grained, burrow-mottled silty sandstone, interbedded with medium-gray to grayish-black, phyllitic shales 1 to 3 m thick. Top of the formation consists of grayish-black phyllitic shale 50 to 66 feet (15 to 20 m) thick. The Araby Formation is present on the eastern side of the Frederick Valley synclinorium. Thickness of the Araby Formation is estimated at 300 feet (100 m). 04-02-03-03 DMUHeader1 --- --- 255 166 184 no pattern DS1 Sandstone High DMU_102
123 Cu Urbana Formation Urbana Formation Cambrian Predominately moderate olive brown to light olive gray, calcareous metagraywacke and metasiltstone. Poorly sorted, graded, cross-bedded, and ripple marked. Contains light olive gray and light brownish gray very calcareous metasandstone and quartzite. Fine- to coarse-grained, thin- to medium-bedded, crossbedded, pitted, friable, lensoidal and discontinuous. Interbedded with light-brown, laminated metasiltstone. Also contains light-gray to greenish-gray, thin-bedded, crystalline marble. Laminated beds of indeterminate thickness are marked by seams of sericite and chlorite. Poorly exposed; produces distinctive reddish-orange soil. 04-03-01-01 DMUHeader1 --- --- 255 191 191 no pattern DS1 Metasedimentary rock High DMU_123
124 Cuq Urbana Formation, quartzite Urbana Formation, quartzite Cambrian Light olive gray and light brownish gray, coarse-grained, thin- to medium-bedded, cross-bedded, pitted, vuggy, friable, lensoidal, and discontinuous quartzite. 04-03-01-01-01 DMUHeader1 --- --- 255 166 166 no pattern DS1 Quartzite High DMU_124
125 Csq Sugarloaf Mountain Quartzite Sugarloaf Mountain Quartzite Cambrian Pinkish-gray to white, fine-to medium-grained granular quartzite. Medium-bedded to massive, well-sorted, graded, crossbedded and ripple marked. Quartzite, interbedded with seldom-exposed moderate-brown quartzose metasiltstone and dusky blue laminated metasiltstone similar to that of the conformably overlying Urbana Formation, underlies topographic swales. Lower, middle, and upper members (informal) are not separately mapped based on topographic expression of ridge-forming units since the quartzites are virtually identical; total thickness is approximately 2000 feet (600 m). 04-03-01-02 DMUHeader1 --- --- 255 184 209 no pattern DS1 Quartzite High DMU_125
122 CZwm Wakefield Marble Wakefield Marble Late Proterozoic? Cambrian? Predominately white to gray, massive to banded or bedded crystalline marble, but also contains dark-gray, bluish-gray, pale green, and purple marble and interbeds of green and purple phyllite. Some zones or layers of the marble are made up primarily of calcite, whereas others are primarily of dolomite. Zones of complex internal folding, boudinaged layers, and purple brecciated zones occur through the unit. Thickness is estimated to range between 3 to 500 feet (1 to 150 meters). 04-03-02-01 DMUHeader1 --- --- 199 207 237 no pattern DS21 Meta-carbonate rock High DMU_122
112 CZscb Sams Creek Formation, metabasalt Sams Creek Formation, metabasalt Late Proterozoic? Cambrian? Dark greenish gray to medium bluish gray, aphanitic to porphyritic, massive to schistose metabasalt composed of chlorite, epidote, quartz, altered plagioclase, actinolite, hornblende, and albite; igneous texture is locally preserved and pods of epidosite are common; includes some metaconglomerate composed of greenstone pebbles and cobbles, local pillow structures, and hyaloclastite. 04-03-02-02-01 DMUHeader1 --- --- 151 182 221 no pattern DS1 Meta-mafic rock High DMU_112
113 CZschp Sams Creek Formation, hematite phyllite Sams Creek Formation, hematite phyllite Late Proterozoic? Cambrian? Bluish-purple, hematite-rich phyllite, resembles Ijamsville Phyllite (Southworth et. al, 2008). 04-03-02-02-02 DMUHeader1 --- --- 162 178 196 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_113
127 CZscl Sams Creek Formation, metalimestone Sams Creek Formation, metalimestone Late Proterozoic? Cambrian? Light-gray, thinly layered, argillaceous metalimestone (Southworth et. al, 2008). 04-03-02-02-03 DMUHeader1 --- --- 144 153 177 no pattern DS4 Meta-carbonate rock High DMU_127
115 CZscm Sams Creek Formation, marble Sams Creek Formation, marble Late Proterozoic? Cambrian? Brownish-gray to grayish reddish purple, massive to thin-bedded, calcitic and dolomitic marble containing quartz sand. Includes minor calcareous metasiltstone. 04-03-02-02-04 DMUHeader1 --- --- 120 136 197 no pattern DS1 Meta-carbonate rock High DMU_115
116 CZscmp Sams Creek Muscovite Phyllite Sams Creek Muscovite Phyllite Late Proterozoic? Cambrian? Light bluish gray, dusky yellow, and moderate orange pink, muscovite-chlorite phyllite containing albite porphyroblasts, quartz, and hematite dust. Contains minor metasiltstone. Lithologically distinct from rocks of the Ijamsville Phyllite and Marburg Formation. 04-03-02-02-05 DMUHeader1 --- --- 208 205 207 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_116
117 CZscq Sams Creek Formation, quartzite Sams Creek Formation, quartzite Late Proterozoic? Cambrian? Light-gray to grayish-green, medium-grained, thin-bedded to massive quartzite and minor calcareous sandstone. Contains detrital plagioclase, orthoclase, and polymictic quartz. Bedding is defined by concentrations of heavy minerals. Light-gray, medium- and coarse-grained quartzite, locally calcareous and cross-bedded also present. 04-03-02-02-06 DMUHeader1 --- --- 162 119 169 no pattern DS1 Quartzite High DMU_117
118 CZscqp Sams Creek Formation, quartzite within phyllite subunit Sams Creek Formation, quartzite within phyllite subunit Late Proterozoic? Cambrian? Light-tan to light grayish green to light silvery gray. The micas and chlorite are typically segregated into prominent pinstripe laminations spaced 0.4 to 1.2 inches (1 to 3 cm) apart and parallel to cleavage. Resistant to weathering; crops out extensively and commonly forms low ridges capped by a thin sandy soil. Corresponds to the Ijamsville mica-chlorite-quartz phyllite of Fisher (1978) and to the Gillis Formation of Edwards (1986). 04-03-02-02-07 DMUHeader1 --- --- 167 145 187 no pattern DS1 Metasedimentary rock High DMU_118
119 CZscs Sams Creek Formation, metasiltstone Sams Creek Formation, metasiltstone Late Proterozoic? Cambrian? Metasiltstone, phyllite, quartzite, and metagraywacke, undifferentiated. Light-brown metasiltstone interbedded with quartzite and calcareous metasandstone. Bedding can be recognized except where transposed in shear zones adjacent to faults. Muscovite phyllite containing albite porphyroblasts and elongate blebs of chlorite is interpreted to be a metatuff. 04-03-02-02-08 DMUHeader1 --- --- 141 130 159 no pattern DS1 Metasedimentary rock High DMU_119
120 CZscsr Silver Run Limestone Member Sams Creek Group, Silver Run Limestone Member Late Proterozoic? Cambrian? Medium to dark bluish gray, fine-grained, thin-bedded to laminated, siliceous to argillaceous or micaceous limestone, interbedded with minor amounts of black to silvery gray phyllite. Bedding ranges from 1/4 inch to 4 inches (0.5 to 10 cm) in thickness and exposures exhibit tight internal folding and strong penetrative cleavage. Thickness of unit is estimated to range between 10 to 100 feet (3 and 30 meters). 04-03-02-02-09 DMUHeader1 --- --- 217 217 217 no pattern DS1 Limestone High DMU_120
121 CZsctp Sams Creek Formation, tuffaceous phyllite Sams Creek Formation, tuffaceous phyllite Late Proterozoic? Cambrian? Grayish red-purple and bluish-gray, variegated, vesicular phyllite with light-gray streaks and blebs of tuffaceous phyllite. 04-03-02-02-10 DMUHeader1 --- --- 209 219 244 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_121
103 CZi Ijamsville Phyllite Ijamsville Phyllite Late Proterozoic? Cambrian? Dusky blue, grayish-blue, very dusky red-purple, greenish-gray to pale olive phyllite, phyllonite, and minor slate. Phyllite contains mostly muscovite and chlorite. Lustrous sheen from mica and dark color results from abundant hematite dust. 04-03-02-03 DMUHeader1 --- --- 235 173 194 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_103
104 CZiq Ijamsville Phyllite, quartzite Ijamsville Phyllite, quartzite Late Proterozoic? Cambrian? Yellowish-gray, fine- to medium-grained, sericitic quartzite locally intervenes between phyllite and metabasalt. 04-03-02-03-01 DMUHeader1 --- --- 191 128 128 no pattern DS1 Quartzite High DMU_104
105 CZib Ijamsville Phyllite, metabasalt Ijamsville Phyllite, metabasalt Late Proterozoic? Cambrian? Dark-green and schistose metabasalt composed of chlorite, epidote, and quartz. Rare pillows locally preserved. Mapped as thin unit east of Martic thrust fault contact with Urbana Formation; one small body mapped in fault slice near confluence of Potomac and Monocacy Rivers (Southworth et. al., 2008). 04-03-02-03-02 DMUHeader1 --- --- 189 190 129 no pattern DS1 Meta-mafic rock High DMU_105
106 CZic Ijamsville Phyllite, conglomeratic metagraywacke Ijamsville Phyllite, conglomeratic metagraywacke Late Proterozoic? Cambrian? Light-gray and green, medium- to coarse-grained metagraywacke with white quartz pebbles, variegated phyllite, and green chloritic matrix. 04-03-02-03-03 DMUHeader1 --- --- 217 140 166 no pattern DS1 Metasedimentary rock High DMU_106
107 CZil Ijamsville Phyllite, metalimestone Ijamsville Phyllite, metalimestone Late Proterozoic? Cambrian? Light bluish gray to medium light gray, thin-bedded, laminated, carbonaceous and argillaceous metalimestone; and minor, medium dark gray, finely laminated, carbonaceous phyllite. Thin unit mapped from confluence of Potomac and Monocacy Rivers for about 5 km to the southeast. Small body located above flood plain of Linganore Creek, east of Frederick, Md. 04-03-02-03-04 DMUHeader1 --- --- 151 127 102 no pattern DS1 Meta-carbonate rock High DMU_107
108 CZim Ijamsville Phyllite, marble Ijamsville Phyllite, marble Late Proterozoic? Cambrian? Light olive gray, sandy limestone and dusky red, calcareous quartzite occurs within phyllite locally. 04-03-02-03-05 DMUHeader1 --- --- 204 140 179 no pattern DS1 Limestone High DMU_108
109 CZip Ijamsville Chlorite Phyllite Ijamsville Chlorite Phyllite Late Proterozoic? Cambrian? Light olive gray and greenish-gray, chlorite phyllite and metasiltstone. 04-03-02-03-06 DMUHeader1 --- --- 209 153 163 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_109
110 CZmb Marburg Formation Marburg Formation Late Proterozoic? Cambrian? Buff to light olive green quartz-muscovite phyllite with subordinate silvery gray quartz-paragonite-muscovite-chlorite phyllite and muscovite-quartz phyllite. Contains abundant limonite cubes, up to 2 cm across, that are pseudomorphs after pyrite. Hematite and tourmaline are common accessory minerals. Very poorly exposed; weathers easily into thick, resistant saprolite containing abundant chips of phyllite. Underlies broad, gently sloping hills. Corresponds to select parts of the Ijamsville muscovite phyllite of Fisher (1978). 04-03-02-04 DMUHeader1 --- --- 191 153 179 no pattern DS1 Slate and phyllite, of sedimentary-rock origin High DMU_110
111 CZmbq Marburg Formation, quartzite Marburg Formation, quartzite Late Proterozoic? Cambrian? Tan to reddish quartzite. Beds of quartzite 15 to 60 cm thick (6 to 24 inches) interbedded with muscovite and chlorite phyllites. Very resistant to weathering. Corresponds to the parts of the Ijamsville quartzite of Fisher (1978) that are associated with phyllite now included in the Marburg Formation. 04-03-02-04-01 DMUHeader1 --- --- 149 152 128 no pattern DS1 Quartzite High DMU_111

Glossary

OBJECTID Term Definition DefinitionSourceID _ID
72 abandoned mine Mine: An underground excavation for the extraction of mineral deposits, in contrast to surficial excavations such as quarries. The term is also applied to various types of open-pit workings. DS1 GLID_72
68 bedding The arrangement of sedimentary rocks in beds or layers of varying thickness and character; the general physical structural character or pattern of the beds and their contacts within a rock mass, such as cross-bedding and graded bedding; a collective term denoting the existence of beds. Also, the structure so produced. The term may be applied to the layered arrangement and structure of an igneous or metamorphic rock. DS1 GLID_68
1 certain Identity of a feature can be determined using relevant observations and scientific judgment; therefore, one can be reasonably confident in the credibility of this interpretation. FGDC-STD-013-2006 GLID_1
10 cleavage A locally planar fabric in an unmetamorphosed or weakly metamorphosed, fine-grained rock defined by either the tendency of a rock to split in a particular direction, a preferred orientation of crystal planes in mineral grains, or a preferred orientation of inequant grain shapes; it is a produce of deformation or metamorphism. DS1 GLID_10
11 contact A plane or irregular surface between two types or ages of rock; examples are faults, intrusive borders, bedding planes separating distinct strata, and unconformities. DS1 GLID_11
16 DMUHeader1 Formation header, bolded text, no indent. This format is used for Formations, members, sub-units, Quaternary deposits, and basement complex. DS2 GLID_16
12 fault A discrete surface or zone of discrete surfaces separating two rock masses across which one mass has slid past the other. DS1 GLID_12
73 flow banding Intersection of igneous or metamorphic layering with an outcrop surface. It may be produced by such processes as flow of geterogeneous material *e.g. flow layering of rhyolites) or successive deposition of layers of different materials (cf: phase layering) Although the term strictly describes the appearance of a two-dimensional feature on a rock exposure, it is commonly used for any "roughly planar heterogeneity in igneous rocks, whatever its origin" (Wager and Brown, 1967, p.5) DS1 GLID_73
13 fold axis A line which, when moved parallel to itself, traces out a folded surface. It applies only in the case of cylindrical folds. DS1 GLID_13
71 foliation A general term for a planar arrangement of textural or structural features in any type of rock, esp. the locally planar fabric in a rock defined by a fissility, a preferred orientation of crystal planes in mineral grains, a preferred orientation of inequant grain shapes, or from compositional banding. In igneous rock, planar parallelism of flaky or tabular mineral and mineral aggregates, slabby xenoliths, or flattened vesicles as well as compositional layering. Inmetamorphic rocks, planar parallelism of flaky minerals and compositional layering. DS1 GLID_71
62 High High level of confidence that GeoMaterial term accurately and appropriately describes the map unit. FGDC-STD-013-2006 GLID_62
15 joint A planar fracture, crack, or parting in a rock, without shear displacement; the surface is usually decorated with a plumose structure. Often occurs with parallel joints to form part of a joint set. DS1 GLID_15
49 lineation A general, nongeneric term for a locally linear structure or fabric in a rock, e.g. flow lines, scratches, striae, slickensides or slickenfibers on a single surface; linear arrangements of components in sediments; or axes in folds. Lineation in metamorphic rocks include aligned rod-shaped and/or elongate minerals grains, crenulation fol axes, and the lines of intersection between bedding and cleavage or any two sets of oriented surfaces. DS1 GLID_49
74 mine An underground excavation for the extraction of mineral deposits, in contrast to surficial excavations such as quarries. The term is also applied to various types of open-pit workings. DS1 GLID_74
75 minor fold hinge Hinge: The locus of maximum curvature or bending in a folded surface, usually a line. DS1 GLID_75

Database Inventory

This summary of database content is provided as a convenience to GIS analysts, reviewers, and others. It is not part of the GeMS compliance criteria.

DataSources, nonspatial table, 23 rows
DescriptionOfMapUnits, nonspatial table, 124 rows
GeoMaterialDict, nonspatial table, 101 rows
Glossary, nonspatial table, 15 rows
GeologicMap, feature dataset
    ContactsAndFaults, polyline feature class, 10994 rows
    MapUnitOverlayPolys, polygon feature class, 1074 rows
    MapUnitPolys, polygon feature class, 1681 rows
    OrientationPoints, point feature class, 1522 rows