This is one of those situations where barcoding would be really useful. As far as I can tell based on the checklists, this is either Helminthoglypta diabloensis, known from a wide swath of montane regions in the East Bay, or H. nickliniana ssp. bridgesii, known from a small region around San Pablo and North Berkeley. Pilsbry describes them both as having 6.5 whorls, both have this kind of sculpture with bumps on the striations, and they seem like they should be the same size (though H. diabloensis might have a slightly more depressed spire), so really all I have to go on is very, very fine scale geography. I bet they're the same species.

Found under a log with the two dead shells that follow on Merritt College campus, on the edge of a stand of coyote bush and a marginally disturbed field. Surrounding area is largely housing, the college buildings, but also oak woodland and chaparral.