Quaternary Felsic Intrusions in the Western US

Quaternary Felsic Vents in the Great Basin. Oregon data uses a scale of 1:500,000. The remaining data use a scale of 1:1,000,000.

Source:
Nevada Bureau of Mines and Geology (NBMG)
ftp://ftp.nbmg.unr.edu/pub/geothermal/03_Geology_Data/