Smalls Falls Formation, undivided

Very rusty weathering, thinly bedded sulfidic-graphitic schist and pyrrhotitic calc-silicate granofels. Eastern facies equivalent to lower part of the Fitch Formation. Locally mapped as Francestown Formation of Nielson (1981) in southern New Hampshire.
State New Hampshire
Name Smalls Falls Formation, undivided
Geologic age Upper to Middle Silurian (Ludlovian and Wenlockian)
Lithologic constituents
Metamorphic > Schistthinly bedded sulfidic-graphitic schist
Metamorphic > Granoblastic > Granofelspyrrhotitic calc-silicate granofels
Comments Part of the Central Maine Composite Terrane (Central Maine Trough) - Variably metamorphosed sedimentary and volcanic rocks of greenschist to granulite facies, locally migmatized. Area includes structural belts between the Monroe fault on the west and the Campbell Hill fault on the east; that is, the Bronson Hill anticlinorium, Piedmont allochthon, Kearsarge-central Maine synclinorium, central New Hampshire anticlinorium, and Rochester-Lebanon (Maine) antiformal synclinorium.

Lyons, J.B., Bothner, W.A., Moench, R.H., and Thompson, J.B., Jr., 1997, Bedrock Geologic Map of New Hampshire: Reston, VA, U.S. Geological Survey Special Map, 2 sheets, scale 1:250,000.

Nielson, D.L., 1981, The bedrock geology of the Hillsboro quadrangle, New Hampshire: New Hampshire Department of Resources and Economic Developement Bulletin 8, 76 p.

NGMDB product
Counties Belknap - Carroll - Coos - Grafton - Hillsborough - Merrimack - Rockingham - Strafford