|Name||Ordovician Kennebec Formation|
|Comments||Named for Kennebec River. Type locality is 1/4 mi northeast of Somerset Junction on northwest side of abandoned railroad right-of-way on northwest side of west branch of Kennebec River, Brassua Lake 15-min quad, northern Somerset Co., western ME. Occurs in belt about 5 mi long northeast to southwest through Somerset Junction. Consists of olive-drab, white-weathering, massive felsite and rhyolite tuff. Thickness unknown, probably from a few hundred feet to a thousand feet. Contact relationships unknown. Report includes geologic map and correlation chart. (ME003) Unit description from USGS GEOLEX website (ME078). W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite Protolith T - Rhyolitic volcanic rocks|
|Primary rock type||rhyolite|
|Secondary rock type|
|Other rock types|
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic, tuff)W - Weakly metamorphosed; contains local occurrences of prehnite and pumpellyite Protolith T - Rhyolitic volcanic rocks
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.