Rhyolite (Miocene).

Rhyolite tuffs and flows (14-8 Ma); includes Juniper Mountain volcanic center, tuff of Little Jacks Creek, Cougar Point Tuff, tuffs in the Mt. Bennett Hills, and Arbon Valley Tuff Member of Starlight Formation. Volcanic sources include Owyhee-Humboldt (13.8-12.0 Ma), Bruneau-Jarbidge (12.5-11.3 Ma), Twin Falls (10.0-8.6 Ma), and Picabo (10.2 Ma) volcanic centers. (Quaternary to Eocene Continental Volcanic and Intrusive Rocks).
State Idaho
Name Rhyolite (Miocene).
Geologic age Miocene
Lithologic constituents
Major
Igneous > Volcanic > Felsic-volcanic > Rhyolite (Pyroclastic-tuff, Flow)
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 Ada - Blaine - Camas - Cassia - Elmore - Gem - Gooding - Lincoln - Owyhee - Power - Twin Falls