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Re: Brachiopod - IMAGE

Posted by guide on December 27, 1997 at 03:11:29:

In Reply to: Brachiopod posted by R.S. on December 27, 1997 at 00:50:43:

: I found this little shell (about 9mm from apex to rim) lying among the fragments of shale at the southern site in the Marble Mountains. It is apparently an extinct brachiopod, Mickwitzia occidens, Walcott (1900), according to Guillermo. I have noticed that brachiopods occur regularly along with the trilobites in the shale. In this specimen, a trilobite cephalon can be seen beneath and through the shell. Was the shell CaCO3 like modern shells? Or CaPO4? Some of the original shell remains. Perhaps this can be analyzed later. At any rate, I has been 560 my since this specimen has seen the light of day.

: R.S.


Here are two of the images that RS send via e-mail. On the top you see the brachiopod (possibly from the Mickwitzia occidens species) along side a fragment of the cephalon of an Olenellus trilobite. On the bottom image you see a section of a conglomerate of stromatolites (algae - the first organisms on earth).

Brachiopods are almost completely extinct animals that, while having a shape similar to common Bivalves (clams, oysters, mussles, etc.), they are completly different animals. Actually, they taste horribly!

In the early Cambrian (about 560 million years ago), trilobites and brachipods were the first animals to develop hard body parts (skeletons) and hence their sudden appearance in the fossil record. The shale that RS found at the Marbles, with the brachipod and the olenellus cephalon, is a beatiful example of the fantastic historical event of life on earth, the famous Cambrian explosion that ocurred around 560 mya.

RS also presented other images of his Olenellus trilobites finds I will post in this thread.


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