...and never even knew it.
People in Reno are always claiming that Peavine or Mt. Rose are extinct volcanoes. Which is bullshit.
As it turns out though, the Springboat hills on the south side of Reno, right next to Mt. Rose Highway, are classified as an active volcanic field.
The hills are apparently a series of highly eroded rhyolite lava domes that pushed up over one-million years ago. Which makes total sense as even today the area abounds with geothermal activity and has two obsidian deposits.