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Another set of pics from the Dinosaur Research Center.
earthstory reblogged
This is the trophy of my trip to Picketwire. This trace fossil is the cast of a Inoceramid clam. They can get a lot bigger but this is the biggest trace fossil I’ve found that wasn’t attached to ton of boulder. The darker spots are most likely bits of oyster shell.
robinatfossils Large Bivalve from the Yorkshire coast near Kettleness
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earthstory reblogged
Opal fossils showing different types of shells and gastropode from coober pedy.The usa quarter gives some idea of its size
earthstory reblogged
some fossils i collected at field camp!
starting from top right we have:
belemnites ⚡️, pentacrinites ⭐️ , more belemnites, and bivalves (left one is Jurassic, right one is the Cretaceous Inoceramus)
the Inoceramus was found in the Mowry Shale, and the others were found in the Sundance Formation
earthstory reblogged
I need the top one for a counter top.
The niche of the infaunal filter feeder (sedentary organisms living buried in the mud of the sea floor, surviving on plankton and organic detritus filtered from the water column) is occupied in the modern day by bivalved molluscs - clams, mussels, and similar species - which have a near-universal distribution in all water bodies across the globe. However, this monopoly was not always in place, and before the end of the Permian period, stranger forms were found in the world's oceans. Brachiopods are common as fossils, but few groups remain extant. The brachiopoda existed as a rival phylum to the molluscs from the Cambrian period (540 to 480 million years ago) onwards, reaching a peak of diversity around the Devonian (420 to 360 m.y.a.), but they were decimated during the Permo-Triassic extinction event - 250 m.y.a - (where around 90% of marine species were erased by rapid climate changes), and after that point never regained their strength - bivalves had replaced them by the Jurassic, as their extendable siphon tubes allowed them to bury themselves while retaining contact with clean water above the sediment, thus opening up another niche which helped them to better avoid predation.
Before the Brachiopod period in the Devonian and Carboniferous, an extinct molluscan class came to prominence in the infaunal niche. The rostroconch was a clam-like creature, but its two shells were not hinged like a clam - instead, they were firmly joined at the apex, like a taco shell.
As no living rostroconchs remain, their morphology is mostly a mystery, but it is believed that shell had to be periodically broken into two and 're-set' like a damaged bone, in order to allow the animal to grow.
Rostroconchs were most widespread in the Ordovician (480 to 440 m.y.a.), but declined due to a suspected global ice age (the snowball earth hypothesis) occurring at the end of that period. When the brachiopods came to the fore, they existed for a while in the background, but their class was dispatched completely at the Permo-Triassic boundary.
-TJT
Information on the Rostroconchia is hard to find online, as they have rarely been discussed outside specialist publications. To see some rostroconch fossils, visit http://northtexasfossils.com/rostroconchia2.htm where the beautiful photo of an Apotocardium specimen was found.
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mohem74
Yesterdays find from the play area at a splash playground. Having a hard time figuring out what is fossil and what is not, so I just grabbed a bit of it all😁
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astoneforeveryhome
Fossil Friday ~ This fossil tabulate coral has a surprise on the back. You can see a bivalve bored into the coral and got fossilized right along with it! Tabulate coral form hexagonal cells out of calcium carbonate (calcite). This was a colonial variety of coral, with tiny coral polyps all growing together. It’s unclear if this bivalve was using the coral reef as an anchor point to protect itself against tidal forces, or if it was nibbling on the coral polyps themselves. Either way they are now locked together in time. Kyle found this piece while rockhounding in Barbados💎
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geology.life
A beautiful Bivalve from the Widder Formation . Was quite difficult cleaning this fossil and luckily I lost nothing .
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mikeharrisonfossils
A little pyrite nodule I found on the Jurassic Coast of Dorset UK 🇬🇧 Its barely bigger than my thumb nail!!😱 Just look 👀 at all those little ammonites! There's even a little bi-valve amongst them! An added bonus as there's ammonites on both sides!! It's even got the Rooks squawking! 😉
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nscrystals
Calcite in a Fossil Clam Shell - Ruck's Pit, Florida. Sold
I used to dig these back when the true locality for this material was open from the time that I was 16 until I was about 23. I have cleaned and sold more of these than I can possibly try to recall but I still never get tired of seeing a truly great one. We managed to find one of the original locality owners and subsequently We have a only few of these great quality ones available for sale. If you havent managed to get a great one of these and you collect fossils or calcite or things which are just great and aesthetic I would not recommend missing one of these.
These are known to come the pliocene era. When the clams and whelks, among other species, had cavities they would sometimes form sharp, golden calcite crystals inside like these. Finding them with large, gemmy crystals was never common, especially undamaged.
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- On one side this may look like just a ordinary clam shell but when you flip it over it contains beautiful golden calcite crystals. The crystals formed when the clam died and a cavity formed allowing the crystals to develop. Took over two million years to do this. Found on the east coast of Florida in Brevard County.
capturing_the_cosmos
Source: instagram.com
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prehistoric_content
A beautiful bivalve I found and prepared. All of the shell is beautifully preserved, unfortunately the back end was revealed and has been weathered a bit.
This bivalve dates back to the early Jurassic and would have seen many marine reptiles in its lifetime. As well as living during a pinnacle time of the dinosaurs.
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