Well, it looks like another quest in search of vanished information. I've been trying to find photos of the short-lived North Beach Auditorium. And we're not talking San Francisco. This is Santa Monica's North Beach.
The Auditorium opened in 1901 as an addition to the 1893 bathhouse. It got a little action for a few years but was soon eclipsed by the more opulent developments in Ocean Park and Venice.
The photo here is an 1898 view of the bathhouse from the Santa Monica Public Library. On their website: a larger view.
There seem to be lots of bathhouse views (both inside and out) but nothing indicating where in the complex the auditorium was or what it looked like.
You'll find what I have so far on the new North Beach Auditorium page.
And if you're interested in theatres on the beach farther south, see the Venice and Ocean Park Theatres page.