STROMATOLITE

Here's one where the center rotted out and became lined with quartz crystals.

Yes, in this location in Wyoming most of them are quite round. Sometimes they are in clusters and sometimes flattened.

Definitely stromatolite..and it looks like the stuff I've collected near Wampsetter Wyoming.

@rwa30036 Read John McFee's book "Rising From the Plains." It's a charming story in addition to being a fascinating tale of Wyoming's geological history. It might help explain how those stromatolites came to be. Time for a re-read on my part. It's been a few years.

If you like them I'd recommend his whole Annals of the Former Wold series: "In Suspect Terrain" and "Assembling California." I once aspired to be a writer but this guy's so good I wonder why I even tried.

Man, you guys are making me jealous! While I can dig up a massive assortment of interesting rocks, the heavy glacier activity around here means finding things in situ is impossible. Spent my whole life in Minnesota and Wisconsin, never even considered that in situ mounds are a thing!

How about those stromatolite slab prices !

So in Florida coral/shells/bones readily mineralize or silicify Randy, but wood and tissue rarely silicify. Perhaps this is why stromatolites are not preserved there commonly. The large specimen above is likely devoid of much silica as are the soft limestone rich coral fossils of south Florida. The soft south Florida limestone is cut to make those fancy Miami mansions ! Maybe I can find an image of S Florida limestone.

They cut it with a chain saw . To run an underground water line they often have to saw a groove in solid limestone too. No silica to be had...



As it ages the coral patterns emerge, but I have never seen what looks like stromatolite patterns in that limestone.:

Here's some Kambaba Jasper from Madagascar. It's stromatolite also.

James, I'm finding most of them at about 6700' and the lowest parts of the southwest region of the state that I play around in is probably near 6500'.

I find some palm wood in the area along with sea level fossils. That area was the western beach of the Great Western interior seaway for a time and the rich gas and oil deposits seem to indicate the area was near sea level and at tropical latitudes at one time. Everything indicates a massive uplift in the past because Wyoming has a very high average elevation in the western half of the state.