Pershing Drive sits at the top of the south end of the Piedmont block at nearly its highest point, just under 800 feet. At one end of the road is a long exposure of rugged Franciscan chert that is exquisitely integrated into the landscaping, which includes native oaks as well as the usual plantings. It is a challenge to photograph but a delight to see in person.
This is the high-grade, bleached and sometimes greenish banded chert of the Piedmont block rather than the beautiful red ribbon chert of the Marin Headlands. Its outcrop appears on the Oakland geologic map east of Piedmont’s Tyson Lake. The very steep slope on its bayward side is interpreted as a thrust fault separating the higher Franciscan melange from the lower Franciscan sandstone. Melange is not generally considered a strong stone by geotechnical engineers, but recent research shows that it depends. This melange is the best bedrock in Oakland, and worthy of its gracious and picturesque neighborhood.
Oakland Geology 
26 October 2020 at 2:17 pm
Questions actually:
Re comment on the last image: Is this an overthrust fault? Is the sandstone younger than the now overlying chert?
Is the chert radiolarian or porcellanite, diatomaceous chert, like the rest of the Piedmont formation???
26 October 2020 at 5:50 pm
It’s slickensides, in metachert of the melange zone.