For a spot with such all kinds of rocks, Oakland isn’t an incredible searching floor for fossils, not less than not for amateurs. However you by no means know. I’ll get into the rocks in subsequent posts, however at the moment let’s try the youngest slice of time, recorded in our sediments.
The lowlands close to the Bay have ice age fossils, buried within the sand and gravel and clay — alluvium — that consistently wash down from the rising Oakland Hills. They date from late within the Pleistocene epoch, only a few hundred thousand years outdated at most. They’re precise, unmineralized bones, not petrified.
California was crawling with massive mammals till very lately in geologic time. It was an epic scene each bit as spectacular as something in Africa. Bones of those creatures, virtually at all times separated and damaged, have been present in alluvium in Oakland and everywhere in the East Bay. Bison legbones. Enamel of archaic horses and camels. Mastodon molars, football-sized, made to chew twigs and bark and leaves. Fangs of the formidable short-faced bear. It’s odd to me, although I’m no skilled, that now we have no examples of the sabertooth cat, Smilodon californicus, marquee species of the late Pleistocene. This man.
Smilodon from La Brea on the UCMP. The smaller skeleton is that of a home cat.
At the very least, the UC Museum of Paleontology doesn’t. The good UCMP assortment comes virtually solely from the tar pits at Rancho La Brea, in Los Angeles, and McKittrick simply north of Taft within the San Joaquin Valley. Hundreds of sabertooth cats have been trapped in tar and died in that bizarre setting over the millennia.
Oakland’s fossils of late Pleistocene megafauna — mastodon, sloth, camel, bison, bear — got here to UCMP from excavations in clayey alluvium: the Posey Tube to Alameda (1927), the pond at Montclair Park (1939), the Coliseum website (1964) and up close to Oak Knoll (1964), amongst others. The 2 higher-elevation websites are dips within the topography associated to the Hayward fault, the place bones have been buried shortly, protected from squirrels and decay.
Elbow bones of Arctodus simus, short-faced bear, from the Posey Tube excavation. Picture by Steve Edwards, used with permission. UCMP report
These animal fossils, categorized as a Rancholabrean fauna, characterize a group that dominated California and the remainder of North America from a few half-million years in the past to only the opposite day, 10,000 BCE or so. A lush savannah of brush and grass supported the big herbivores, and the big carnivores, from sabertooths to condors, fed upon them.
Molar of mastodon Mammuthus columbi from the Montclair pond. Picture by Steve Edwards, used with permission.
We’ve got components of Oakland fabricated from alluvial sediment like these websites, however a lot older — the gravelly foothills on the downhill facet of Piedmont that I discuss with because the Fan. I infer them to be as outdated as about one million years. This alluvium hasn’t yielded any bones, to my information, but when it ever does I predict they’ll characterize the sooner Irvingtonian fauna. That will be thrilling as a result of the Irvingtonian is outlined by a spectacular set of fossils dug from a gravel quarry, again within the Nineteen Forties, within the Irvington district of Fremont. It might be fascinating to check one other Irvingtonian locality. (There’s additionally one close to Chowchilla.) Within the meantime, you may see real Irvington fossils on the Kids’s Pure Historical past Museum in Fremont and be taught in regards to the metropolis’s effort to construct a much bigger museum in Sabercat Historic Park.
We should always hold our eyes open downtown, too. The Emporium constructing at Broadway and twentieth, now generally known as Uptown Station, was in-built 1928 with two basement ranges, and the excavators uncovered historical tree stumps down there. That forest would have grown not less than thirty thousand years in the past, maybe a lot earlier. As new downtown buildings dig their footings beneath the Merritt Sand, we could discover extra.
Kneebone of big floor sloth Glossotherium from the Coliseum website. UCMP report Picture reproduced underneath Inventive Commons Attribution 3.0 (CC-BY-3.0) license.
Preserve watching the bottom!
