Devonian Hobbstown Formation (MEDhb;0)

State	Maine
Name	Devonian Hobbstown Formation
Geologic age	Devonian
Lithologic constituents	Major Sedimentary > Clastic > ConglomerateGS - Greenschist facies; Protolith H - Lithic sandstone and conglomerate Sedimentary > Clastic > Sandstone > ArkoseGS - Greenschist facies; Protolith H - Lithic sandstone and conglomerate
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.
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. Boucot, A.J., 1961, Stratigraphy of the Moose River synclinorium, IN Contributions to general geology, 1959: U.S. Geological Survey Bulletin, 1111-E, p. E153-E188. https://pubs.er.usgs.gov/publication/b1111E 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. https://pubs.er.usgs.gov/publication/i1898D Boucot, A.J., 1969, Geology of the Moose River and Roach River synclinoria, northwestern Maine: Maine Geol. Surv., Bull. 21, 123 p. US Geological Survey, 2005, National Geologic Map Database, Geologic Names Lexicon "GEOLEX", http://ngmdb.usgs.gov/Geolex/.
NGMDB product	NGMDB product page for 16547
Counties	Somerset

State

Maine

Name

Devonian Hobbstown Formation

Geologic age

Devonian

Lithologic constituents

Major

Sedimentary > Clastic > ConglomerateGS - Greenschist facies; Protolith H - Lithic sandstone and conglomerate

Sedimentary > Clastic > Sandstone > ArkoseGS - Greenschist facies; Protolith H - Lithic sandstone and conglomerate

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.

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.

Boucot, A.J., 1961, Stratigraphy of the Moose River synclinorium, IN Contributions to general geology, 1959: U.S. Geological Survey Bulletin, 1111-E, p. E153-E188.

https://pubs.er.usgs.gov/publication/b1111E

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.

https://pubs.er.usgs.gov/publication/i1898D

Boucot, A.J., 1969, Geology of the Moose River and Roach River synclinoria, northwestern Maine: Maine Geol. Surv., Bull. 21, 123 p.

US Geological Survey, 2005, National Geologic Map Database, Geologic Names Lexicon "GEOLEX", http://ngmdb.usgs.gov/Geolex/.

NGMDB product

NGMDB product page for 16547

Counties

Somerset