Indian Grinding Rock State Historic Park

About 12 miles east of Jackson is this intriguing state park. There is a campground and a large glade surrounded by mountains. In this pleasant valley we find a display of bark houses. These resemble Teepees but they are built of cedar poles and bark interwoven with willow or grapevines. These are the style of homes built by the Miwok peoples who lived here.

Nearby, we find the oak trees that sustained the Miwok people with the annual harvest of acorns. They did have some competition from the acorn woodpeckers. These industrious creatures bore holes in the trees and stuff acorns in them for later retrieval. If you look closely, you'll see that some of the holes still have the acorns in them.

The big attraction here is the extensive rock outcropping that the Miwok used to pound and grind the acorns to make flour. This collection of holes is called a Chaw'se.

What makes this Chaw'se unique is that there are petroglyphs interspersed with the holes. According to the brochure,

Chaw’se is the Miwok word for the mortar cups that formed in a stone slab as the Miwok people pounded acorns and other seed into meal. The largest chaw’se example can be seen at the park. The main grinding rock also features 363 petroglyphs —including circles, animal and human tracks, and wavy lines. Some of these carvings are thought to be as old as two or three thousand years; they are now becoming difficult to see. This association of rock art and bedrock mortar pits is unique in North America. Except for one other small site, Indian Grinding Rock State Historic Park has the only known occurrence of mortars intentionally decorated with petroglyphs.

I was not able to discern any petroglyphs that I could definitely say what they were. They seem to really have faded.

The lighter color streaks you see below may be some of the petroglyphs, but it is hard to tell.