722 Jean Street
This obscure mark is near the Morcom Rose Garden. As I was photographing it I thought it said “C. Donovan,” but now I see that it’s Monohan, an uncommon spelling of Monahan. The initial could be G rather than C, but only another example will help.
(Since I first posted this, I’ve revisited in better light. That’s what this photo shows now.)
Oakland Underfoot 
26 October 2022 at 3:21 pm
Don’t know whether you check out paving along the semi-hidden pathways and steps that run between some city block, but I found a nice 1928 C. MOnohan mark along the inclined pavement along East 25th Street Way, which runs between 14th Avenue and Wallace Street. This is a considerably more legible mark than the 1928 C. Monohan mark on Jean Street. There are a couple of nearbly rectangles along the sidewalk on 14th Avenue that could be other C. Monohan marks but I didn’t see anything inside of them.