Ijamsville Formation (MDif;3)

State	Maryland
Name	Ijamsville Formation
Geologic age	Late Precambrian (?)
Original map label	if
Comments	secondary unit description from USGS Geologic Names Lexicon (ref MD005): Based on stratigraphic interpretation, the age of the Ijamsville Phyllite is changed to Late Proterozoic(?) and Early Cambrian(?). Consists of dusky blue, grayish blue, very dusky red purple, greenish gray to pale olive phyllite and phyllonite with abundant quartz veins and minor slate. Also contains aphanitic to porphyritic greenstone and yellowish gray, fine- to medium-grained sericitic quartzite.
Primary rock type	phyllite
Secondary rock type	slate
Other rock types	meta-argillite; metasedimentary rock; greenstone; quartzite
Lithologic constituents	Major Metamorphic > Metasedimentary > Metaclastic > Phyllite Minor Metamorphic > Metasedimentary > Metaclastic > Metasandstone > Metagraywacke Metamorphic > Metasedimentary > Metaclastic > Metasiltstone Metamorphic > Metasedimentary > Metaclastic > Slate Incidental Metamorphic > Metasedimentary > Metaclastic > Quartzite Metamorphic > Metaigneous > Greenstone
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 Unpublished digital version of the Maryland state geologic map that was digitized by the USGS Water Resources Office in Towson, MD USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Carroll - Frederick - Montgomery