Not the worst coat of arms I’ve seen, and in fact compared to a lot of local government seals/arms it’s fairly restrained.
http://www.sdtreastax.com/images/ttcheader.jpg
The structure in base is the County Administration Building.
http://voiceofsandiego.org/wp-content/uploads/4dbb3b49832fb.image.jpg
I like it. San Diego alsoIITC has a fairly nice COA for the city itself.