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Urbana Formation

Urbana Formation - Dark gray to green sericite-chlorite phyllite, metasiltstone, and quartzite; thin lenses of impure marble and calcareous phyllite occur locally.
State Maryland
Name Urbana Formation
Geologic age Late Precambrian (?)
Primary rock type phyllite
Secondary rock type meta-argillite
Other rock types quartzite; marble
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > Phyllite
Metamorphic > Metasedimentary > Metaclastic > Metasiltstonemeta-argillite
Minor
Metamorphic > Metasedimentary > Metaclastic > Quartzite
Metamorphic > Metasedimentary > Metacarbonate > Marble
Map references
Cleaves, E.T., Edwards, J., Jr., Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.
Unit references
Cleaves, E.T., Edwards, J., Jr., Glaser, J.D., 1968, Geologic Map of Maryland: Maryland Geological Survey, Baltimore, Maryland, scale 1:250,000.
Unpublished digital version of the Maryland state geologic map that was digitized by the USGS Water Resources Office in Towson, MD
Counties Frederick