A story posted yesterday by Nevada Appeal describes the rock art at Lagomarsino Canyon, north of Virginia City, believed to be as much as 10,000 years old.
As a bonus, you might see a few wild horses getting in and out of there. (No paved roads, 4WD recommended.)
The coordinates of the site are 39.442980, -119.567228, according to Google Maps.
Western Horse Watchers Association 