Metasedimentary rock: Variously assigned to the Swauger Formation, Yellowjacket Formation, Lemhi Group, and/or Belt Supergroup along southest Montana-Idaho border (MTYs;0)

Metasedimentary rock: Variously assigned to the Swauger Formation, Yellowjacket Formation, Lemhi Group, and/or Belt Supergroup along southest Montana-Idaho border

Beaverhead Mountains, southwestern Montana - Light gray quartzite with subordinate argillite, siltite, and calc-silicate rocks; unresolved unit that has been variously assigned to Yellowjacket Formation, Lemhi Group, Swauger Formation, or Belt Supergroup. Thickness as much as 2,700 m (8,858 ft).

State	Montana
Name	Metasedimentary rock: Variously assigned to the Swauger Formation, Yellowjacket Formation, Lemhi Group, and/or Belt Supergroup along southest Montana-Idaho border
Geologic age	Middle Proterozoic
Lithologic constituents	Major Metamorphic > Metasedimentary > Metaclastic > Quartzite Minor Metamorphic > Metasedimentary > Metaclastic > Metasiltstonesiltite Metamorphic > Metasedimentary > Metaclastic > Argillite Metamorphic > Metasedimentary > Calc-silicate-rock
References	Vuke, S.M., Porter, K.W., Lonn, J.D., and Lopez, D.A., 2007, Geologic Map of Montana - Compact Disc: Montana Bureau of Mines and Geology: Geologic Map 62-C, 73 p., 2 sheets, scale 1:500,000. This map was digitized in 2012 as a result of a contract between the U.S. Geological Survey and the Montana Bureau of Mines and Geology.
NGMDB product	NGMDB product page for 81651
Counties	Beaverhead - Lewis and Clark - Madison - Ravalli - Silver Bow