Overlook of the Lahontan Valley from Grimes Point, an archaeological site near Fallon, Nevada.  The area houses a large variety of petroglyphs on the desert-varnished boulders as well as a few shallow caves of prehistoric use, notably Hidden Cave.  A trail leads one to the top of Grimes Point where one can see the vast valley, which back then would have been part of Lake Lahontan, an Ice Age lake that occupied much of the region.  The rock type here are leftover tufas which are commonly in this area.