VampCatt 0 Report post Posted April 10, 2017 We recently moved back to Colorado,.,.. Got us a tumbler and rock saw and toys... but need help identifying some rocks - These rocks looked like Petrified wood at first, but then we noticed the top crust has weird swirls /designs. Upon tumbling some, we noticed that the striations and swirls on the crust are almost opalescent looking, hard to tell. Anyone have any idea what these could be?? THANKS! Share this post Link to post Share on other sites
FossilDudeCO 573 Report post Posted April 10, 2017 Hi there! Welcome from Centennial, CO! Can you post some closer photos from various angles of some of these pieces? Any information you can provide about location and age of the sediments would be helpful as well. I am especially interested in that pitted looking one on the left hand side! Share this post Link to post Share on other sites
FossilDAWG 3,783 Report post Posted April 24, 2017 Just saw this post, sorry for the late reply. All your specimens are fragments of large inoceramid clams, likely Sphenoceramus. The fibrous calcite structure is characteristic. The "pitted" one has small oysters (Pseudoperna congesta) attached as epibionts, also a common occurrence. Don Share this post Link to post Share on other sites
jpc 1,977 Report post Posted April 24, 2017 either Inoceramids or calcite layers. Pretty common in Cretaceous marine rocks, of which there are an abundance of on the western slope. Share this post Link to post Share on other sites
