My brother and I went fossil hunting for a few minutes today after breakfast. In the corner of Rodeo, California is a rocky outcrop, composed primarily of Briones Formation siltstone, that juts out into San Pablo Bay. A four-inch-thick statum of Pleistocene seafloor laying atop the siltstone there holds the most densely packed assemblage of fossil invertebrates I thnk I’ve seen.  It’s probably better to call them subfossils: it looks as though the clams, scallops, oysters and all are wearing their original calcium, their shells still translucent and relatively sturdy for their paper-thinness. They are probably the youngest (sub)fossils my brother and I have collected together: they date from the Pleistocene, aboout 125,000 years ago.

It is an industrialized, polluted, not at all pristine landscape. We crawled through holes in chainlink fences, slipped down past cigarette wrappers and beer bottle caps to the shore, where wake from passing barges doused our shoes. The waves had dug out small hollows, halfway between cove and cave, and the fossil layer hung seven feet above the ground.

I am going back soon, and better prepared. And I halfway hope I don’t find anything good: Pleistocene vertebrates have been found in the area, and while taking an oyster or two that would otherwise be ground to sand in this winter’s storms is no big deal, finding a mammoth or a teratorn would mean I’d have to turn myself in so that the real paleontologists could get to it before the teenagers did.

Note:Many old comments were lost in a database crash in 2008. Some conversations may seem to make less sense than they would have. A few will make more sense now.