The Picture Rock Pass Petroglyphs Site is in northern Lake County, Oregon, United States. The site is located near the summit of Picture Rock Pass on land administered by the Bureau of Land Management. The designs were scraped into a basalt boulder by ancient Native Americans, probably between 7,500 and 12,000 years ago. No one knows the meaning of the petroglyph designs. Because of its unique archaeological and cultural significance, the Picture Rock Pass Petroglyph Site was listed on the National Register of Historic Places in 1975.
More information on the Wikipedia page [1].
A website on Oregon Rock Art is [2].