Silurian Perry Mountain formation (MESp;0)

State	Maine
Name	Silurian Perry Mountain formation
Geologic age	Silurian
Original map label	Sp
Comments	Composed of cyclically interbedded, quartz-rich sandstone or quartzite and aluminous, potassium-rich shale. About 600 m thick at type. Similar lithologically to fossiliferous Sangerville Formation. (ME041). Unit description from USGS GEOLEX website (ME078). GS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone
Primary rock type	sandstone
Secondary rock type	shale
Other rock types	quartzite
Lithologic constituents	Major Sedimentary > Clastic > SandstoneGS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone Sedimentary > Clastic > Mudstone > ShaleGS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone Minor Metamorphic > Metasedimentary > Metaclastic > QuartziteGS - Greenschist facies E - Epidote-amphibolite facies AA - Low rank amphibolite facies AB - Medium rank amphibolite facies AC - High rank amphibolite facies Protolith Q - Interbedded pelite and sandstone
Map references	Digital bedrock data downloaded from Maine Office of GIS in September 2005 from http://apollo.ogis.state.me.us/catalog/catalog.asp?state=2&extent=cover#bedrock Bedrock units table (publication date 11/15/2002) downloaded from same site. Permission to redistribute these data granted by Dr. Robert Marvinney, State Geologist of Maine, in September 2006. [http://apollo.ogis.state.me.us/catalog/catalog.asp?state=2&extent=cover#bedrock]
Unit references	Osberg, P. H., Hussey, A.M., and Boone, G. M., 1985, Bedrock geologic map of Maine: Maine Geological Survey, Dept. of Conserv., scale 1:500,000. Moench, R.H. and Pankiwskyj, K.A., 1988, Geologic map of western interior Maine: U.S. Geological Survey Miscellaneous Investigations Series Map, I-1692, 21 p., 1 sheet, scale 1:250,000. [http://pubs.er.usgs.gov/publication/i1692] USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Franklin - Kennebec - Oxford - Penobscot - Piscataquis - Somerset