|Name||Cambrian Grand Pitch Formation|
|Comments||Named for Grand Pitch of East Branch of Penobscot River. Penobscot Co., northeastern ME. Name replaces Grand Falls Formation of Ruedemann and Smith (1935); name was preoccupied. Continuous exposure lines riverbanks for 1000 ft in vicinity of Grand Pitch. At type section, consists of light-greenish-gray, fine-grained quartzite in massive beds interbedded with thinner layers of light-greenish-gray and medium gray slate; and red slate containing OLDHAMIA SMITHI Ruedemann. Proportions of slate increase both upstream and downstream. (ME073) Unit description from USGS GEOLEX website (ME078). W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite; Protolith Q - Interbedded pelite and sandstone Also GS - Greenschist facies; Protolith Q - Interbedded pelite and sandstone|
|Primary rock type||mudstone|
|Secondary rock type||sandstone|
|Other rock types|
Sedimentary > Clastic > SandstoneProtolith Q - Interbedded pelite and sandstone W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite; Also GS - Greenschist facies
Sedimentary > Clastic > Mudstone (Greenschist)Protolith Q - Interbedded pelite and sandstone W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite; Also GS - Greenschist facies
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.
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.
|Counties||Aroostook - Penobscot|