Upper Missoula Group.

Feldspathic quartzite and subordinate siltite and argillite. Includes Mount Shields, Bonner, Striped Peak, and Libby formations in northern Idaho and possibly correlative quartzite north of Salmon and in the Meadow Creek metamorphic sequence east of Elk City. (Mesoproterozoic Belt Supergroup).
State Idaho
Name Upper Missoula Group.
Geologic age Mesoproterozoic
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metaclastic > QuartziteFeldspathic quartzite.
Minor
Metamorphic > Metasedimentary > Metaclastic > MetasiltstoneSiltite.
Metamorphic > Metasedimentary > Metaclastic > Argillite
References

Lewis, Reed S., Link, Paul K., Stanford, Loudon R., and Long, Sean P., Geologic Map of Idaho, 2012, Idaho Geological Survey, Geologic Map 9 (M-9); Scale 1:500,000.

NGMDB product
Counties Benewah - Bonner - Clearwater - Idaho - Kootenai - Latah - Lemhi - Shoshone