Cupule Rock Nevada

Grimes point was on the shore of ancient ice age Lake Lahotan 10,000 years ago. The lake now evaporates faster than it accumulates. This was a marsh 2000 years ago. People have lived here and marked these rocks for thousands of years. Some of these seem to keep track of the seasons and phase of the moon by aligning rocks in indentations (cupules) to match and record celestial body positions. The black surface of the rocks are due to thousands of years of exposure to weather that have developed over the rock engraving. http://www.nvrockart.org/aan_pages/Grimes.html