Lately the city has been fixing up the walks along the waterfront, and they’re well worth a visit. This splendid boulder of slate isn’t on the newest part of the trail—it’s at the foot of Alice Street, just where the Jack London Waterfront leaves off and the Alice Street Mini-Park starts.
I don’t know where they get stones like this; they aren’t from Oakland or even from the Bay area. That’s OK.
Oakland Geology 
25 May 2012 at 9:55 am
That’s an astute observation. I see that the bedrock up there includes a unit called the Salt Springs Slate.
24 May 2012 at 9:32 pm
If I Had to Guess, Have seen rocks like this Around Pardee Reservoir, which is Owned bu the EBMUD, which is Based in Oakland.