The Cambian

Cambrian Paleogeography, Southwestern US (~510 Ma). The passive margin setting continued; fluvial and shallow marine sandstone and mudstone grade westward to shelf carbonate rocks. The slope-rise at the continental margin was the site of deep marine turbidity and slump deposits.

The hingeline marks the sharp, linear zone that separates thin sedimentary rocks of the cratonic interior from westward-thickening sedimentary rocks deposited on the more rapidly subsiding passive margin miogeocline. The hypothetical rifted microcontinent fragments apparently lingered off SW North America during much of the Paleozoic and were accreted to the southwest margin to form parts of Mexico and California in the Mesozoic. From the Late Cambrian through the Devonian, the region was dominated by carbonate deposits across the craton and miogeocline. Slope-rise and adjacent oceanic environments were the site of very fine-grained terrigenous mud and carbonate ooze deposition.

Got that. Well, I'm just looking at the picture. Hmmmm? Need to go look at the fossils from this era. Be right back.

The Precambrian and Paleozoic: Sedimentary rocks from the Precambrian and Early Paleozoic are most often found in the White Mountains, Inyo Mountains, and near Death Valley in Southern California. The Precambrian rocks rarely contain fossils, but deposits from the Cambrian through Devonian contain numerous fossils, such as corals, ammonites, and brachiopods, indicating a shallow, warm water environment teeming with life. The fossil record of the later Paleozoic (Carboniferous and Permian), best represented in Northern California (Shasta and Butte Counties), indicates both shallow and deep water deposits, as well as swamps and estuarine environments. Some of the late Paleozoic rocks are most likely exotic terranes that were carried in from the west as a result of tectonic activity.

Here's a partial list from the University of California Museum of Paleontology of fossils from the Cambian collected in California.
http://www.paleoportal.org/portal/index.php?action=stateperiod&state_id=10&period_id=16

Here's some little guide books to check out.
http://www.powells.com/s?author=B.%20J.%20Tegowski

Finding photos online is difficult. I ordered some books from the library, one specific to inverterbrate fossils of California. Hmmmm? we'll see what I get.

Here's a photo to whet your appetite. There is a Lingulella sp. (unknown), first on the list from the UCMP. Found this awesome photo from China. Comparable occurrence to the Burgess Shale, I guess. Too cool, but they are still ishy, squishy things!















Lingulella chengjiangensis