User:Evert Oldham

I'm an old man, retired and stumbled into a vast personal education opportunity that may have some value to the scientific community. I live in Northwest New Mexico (San Juan Basin) in the river valleys and foot hills of the San Juan Range of the Rocky Mountains. I was collecting small petrified wood gravels for an art project and began exploring the questions of where, in geologic time, they came from. Unsuccessful, I began collecting fossils from the same gravel deposits to see if they might provide a clue. What I discovered was a trove of marine invertebrates: Sponges, Bryozoans, Crinoids, Brachiopods (not so many), Bivalves (not so many), Corals, Hydrozoa, Trace fossils and numerous unidentified. The gravel deposits seem to relate to the Western Interior Seaway – approximately the western shoreline. (Is the mixing of invertebrate fossils and petrified wood explained by costal drift wood? (My original quest.) Mid to late Cretaceous (approximately 95 mya to 80 mya while this collection site was inundated – the deposits underlie the Ojo Alamo and Animas Members and appear to be Kirtland Shale, Upper Shale Member – Upper Cretaceous. Map accuracy does not accommodate the rugged topography more precisely and the unconformity of the basin geology additionally complicates identification. I am in the process of trying to identify the fossils down to the species level. That is the purpose of my participation with species-id.net.

A small photographic sampling of my collection can be seen at: https://www.flickr.com/photos/125316297@N07/albums

All the fossils came from the same formation on the same hillside over a two year period.