Silurian Hersey formation (MESh;0)

State	Maine
Name	Silurian Hersey formation
Geologic age	Silurian
Original map label	Sh
Comments	Secondary unit description from USGS Geologic Names lexicon (ref. ME078): Named the Hersey red shale member of the Pembroke formation for exposures on Hersey Neck, Washington Co., ME. Consists of purplish red fossiliferous shale; includes some gray shale like that of Leighton member. Thickness is 2700 feet. The Hersey is the top member of the Pembroke formation and is separated from the older Leighton gray shale member by rhyolite tuff. Unit is of Late Silurian age. GS - Greenschist facies Protolith Q - Interbedded pelite and sandstone
Primary rock type	shale
Secondary rock type
Other rock types
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > ShaleGS - Greenschist 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. Berdan, J.M., 1971, Silurian to Early Devonian ostracodes of European aspect from the Eastport quadrangle, Maine: Geol. Soc. Amer., Abs. with Prog., v. 3, p. 18. USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Washington