Time Capsule: The Bilger Quarry, 1962 and Today: The Rockridge Shopping Center/Shops at the Ridge
Bilger Quarry. The Oakland Paving Company mined a body of traprock (mapped as Franciscan quartz diorite, a near-basalt), crushed it, and shipped it out via a rail spur that crossed Broadway at 42nd Street and curved toward the former depot at 41st and Shafter streets (you can see the trace in Google Maps).
- From the blog "Oakland Geology, focused on, near and under Oakland, California," written by Andrew Aiden, email@example.com. Used by permission of the blogger.
Photo provided to The Rockridge News by Susan Strahan of College Avenue's Strahan Insurance Services. She had been given it, along with a copy of a site analysis of the property's suitabilty for development, by a business acquaintance who was cleaning out old files