Devonian Hildreths Formation (MEDh;0)

State	Maine
Name	Devonian Hildreths Formation
Geologic age	Devonian
Original map label	Dh
Comments	Usage follows that of Pollock (1987) who assigns it to the Seboomook Group. Occurs in central Maine trough. Consists of thinly bedded calc-silicate rocks, white marble, volcaniclastic graywacke, and black, sulfidic schist. Includes separately mapped euxinic black shale member. Remnants of Hildreths occur in migmatitic gneiss of overlying Mount Blue Formation of Seboomook Group. Age is Early Devonian. (ME011) Unit description from USGS GEOLEX website (ME078). AA - Low rank amphibolite facies; AB - Medium rank amphibolite facies; AC - High rank amphibolite facies; E - Epidote-amphibolite facies; GS - Greenschist facies; Protolith S - Interbedded pelite, sandstone, and limestone and/or dolostone
Primary rock type	calc-silicate rock
Secondary rock type	marble
Other rock types	graywacke; schist
Lithologic constituents
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., Boone, G.M., Bothner, W.A., Boudette, E.L., Hatch, N.L., Jr., Hussey, A.M., III, Marvinney, R.G. and Aleinikoff, J.N., 1995, Geologic map of the Sherbrooke-Lewiston area, Maine, New Hampshire, and Vermont, United States, and Quebec, Canada: U.S. Geological Survey Miscellaneous Investigations Series Map, I-1898-D, 56 p., 2 sheets, scale 1:250,000, Prepared in cooperation with the Maine Geological Survey and the New Hampshire Geological Survey. [http://pubs.er.usgs.gov/publication/i1898D] USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Franklin - Oxford - Piscataquis - Somerset