Bruce invited me to join the forum – I’ve done quite a bit of field work in the Purisima Formation, mostly going after fossil vertebrates (my focus is marine mammals) but I am very familiar with the inverts as well and my master’s thesis (published last year in PLOS One) considers the marine vertebrate taphonomy of the unit. Capitola is one of the taphonomically more informative localities as it spans inner-middle shelf depositional settings. Also, I’m quite proud of the fact that in 2004 I helped others in Santa Cruz county stop a seawall from being built that would have covered over this entire locality – so I am absolutely pleased to hear that you all have started using it as a “teaching laboratory” for educational purposes.
Bruce, I see plenty of Anadara trilineata in that collection of mollusks you received. I may be able to make it down to Capitola while I’m home for Christmas, but more likely than not I’ll ask a couple of my buddies in the area who are dedicated, informed amateurs to collect some of the other more common invertebrates.
As for sharks: rare Carcharodon carcharias teeth can be found in a couple of the horizons, but no Carcharocles megalodon; only a single tooth has been collected from the Purisima, and I collected it from a different locality that is geochronologically older (~7 Ma, as opposed to the ~2.5-5 Ma section at Capitola).
I am more than happy to answer any questions you guys have – please pick my brain! This is one of my favorite localities, and I’ve been visiting the spot since I was in high school ~14 years ago. Cheers, Bobby