phidelt370 Posted April 2, 2018 Share Posted April 2, 2018 (edited) Can anyone help me identify these rocks and whether or not they are fossil imprints? They look like trilobite shapes, but not sure if this is just a natural ripple effect on the rock. Found at Jacalitos Creek in Coalinga, CA. I mostly otherwise find sand dollars and shells in the creek bed. Edited April 2, 2018 by phidelt370 Link to comment Share on other sites More sharing options...
ynot Posted April 2, 2018 Share Posted April 2, 2018 Can not be trilobites, the rocks there are not old enough. They do look like shell pieces, but I think that is just a coincidence. Going to guess they are chert.. 1 Darwin said: " Man sprang from monkeys." Will Rogers said: " Some of them didn't spring far enough." My Fossil collection - My Mineral collection My favorite thread on TFF. Link to comment Share on other sites More sharing options...
Tidgy's Dad Posted April 2, 2018 Share Posted April 2, 2018 I think they are all chert. However, the bottom two and especially the bottom one may have rib patterns from bivalve shells on them. A close up of the ribbed sections may help. 2 Life's Good! Tortoise Friend. Link to comment Share on other sites More sharing options...
DPS Ammonite Posted April 2, 2018 Share Posted April 2, 2018 If it has a hardness of about 7 and the banding goes thru the rock then it is likely a piece of Monterey chert which is common along the coast of cenrtal and Northern California. https://www.researchgate.net/figure/Modes-of-occurrence-of-chert-spheroids-in-the-Monterey-Formation-A-Many-chert_fig8_229542577 https://whatmissinglink.wordpress.com/2014/10/31/nutcracker-man/ 1 My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
caldigger Posted April 2, 2018 Share Posted April 2, 2018 I can definitely agree with that one! That stuff is everywhere here. There is one thing that the central coast has a lot of and that's Cherts and Jaspers. Link to comment Share on other sites More sharing options...
Al Dente Posted April 2, 2018 Share Posted April 2, 2018 They look like oyster shell fragments to me. You can put some vinegar on them to see if they fizz. 2 Link to comment Share on other sites More sharing options...
phidelt370 Posted April 2, 2018 Author Share Posted April 2, 2018 Thanks guys Link to comment Share on other sites More sharing options...
abyssunder Posted April 2, 2018 Share Posted April 2, 2018 My first impression, seeing the specimens, said oysters, so I'll go with that and with Eric. " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
DPS Ammonite Posted April 2, 2018 Share Posted April 2, 2018 @phidelt370 I can see how they might also be worn pieces of Miocene/ Pliocene oysters. Let us know if a knife blade scratches them and if acid causes them to fizz so we can tell you what they are. The left sides of each piece are slightly concave and layered/ corrugated, similar to the hinge area of oysters. My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
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