Mt Irish in the Basin and Range National Monument is known for Pahranagat style anthropomorphic figures. This style of anthropomorphic figure is known only from the Pahranagat Valley of Southern Nevada and its tributaries. The age in unknown but people first inhabited this part of Nevada over 6,000 years ago and likely much earlier than that.

More information here:
http://www.nvrockart.org/aan_pages/MI.html