This is a large part of Oakland you might have never seen.
70 miles of trails.
We were steered there by an explorer who thought she had discovered some bedrock mortars we did not know about in an area closed to the public because it is near a contaminated unsafe area.
There may be bedrock mortars here in this unusual landscape but we did not find them.
These narrow very deep holes we have seen elsewhere and we thought they were for dynamite sticks.
There are quite a few of them on this rocky hilltop.
It turns out they are probably Seismic Boreholes, used to obtain shear and compression wave velocities for a variety of geotechnical applications.
We believe there were Indians everywhere there were freshwater creeks, and beyond.
Bedrock mortars are not necessarily found in all of their ancient village and ceremonial sites.