Oakland’s sidewalks are full of old mason’s marks. They’re like fossils in the city’s hardscape. Since I started paying attention to them a few years back, the oldest have reached a century’s age. There’s a mark on 49th Street that dates from 1906, another at John and Gilbert streets from 1907, and several around town from 1908. Some of the makers operated from addresses that don’t exist any more, such as one from a street number that’s now underneath the Kaiser complex, or from streets that have changed their names. If someone has a blog about them (and why not?), let us know.
Just last week I learned that the operator of the Rockridge Shopping Center quarry was called the Oakland Paving Company. The very next day, I spotted this mark on Claremont Boulevard near The Uplands. Presumably, if we broke this pavement open we’d see gravel made of the quarry’s basalt inside. That is, the quarry produced the aggregate, while the cement came from elsewhere, possibly the giant plant in Davenport, which has produced cement since 1903 (and which I’ll be visiting this weekend). My hypothesis is that the Oakland Paving Co didn’t do much of this labor-intensive retail-type work making sidewalks, which is why its maker’s marks are so rare. But they say the best geologist is the one who’s seen the most rocks, and maybe I just need to see more marks.