Bivalve Fossil ID?

[CMD]

Well, I'm thinking of Roger here, because these are obscure and there might not be enough detail to ID.
Here is what I know. These bivalves are found in quartzite pebbles that are found in conglomerate of the Rhode Island Formation, or one of the other area formations which date to the Pennsylvanian Period, the so-called Coal Age. I have heard that they are themselves Ordovician in age. And I am just wondering if they are clams, or brachiopods, or  :dunno:  Since they are found in conglomerates, a major river must have taken quartzite pebbles downstream to eventually become part of the Pennsylvanian Period formations as a conglomerate member unit. I assume they are marine bivalves. I don't think anybody knows the actual geographic location or origins  for the quartzite pebbles containing these fossils. I found this piece in a Newport Co., RI potato field, while surface hunting for artifacts.
Obviously, it's not expected that fossils preserved in quartzite will be well preserved, but, really, these are not bad at all. Mostly natural casts, with some molds popping out of the rock as well.

The specimen to the right seems to show what look like annual growth rings, and you can see similar rings in other examples if you look closely in the first photo above....


Cortex of pebble showing weathered fossils.

Basically, just wondering what type of bivalve these are, if that can be determined from this specimen.

[JoshinMO]

Nice to see your up and running! Nice topic btw!

[Lithophylic]

Hard to tell from the photos.  You need to find a complete profile to confirm.  It has similarities to the Ordovician Leptobolus; however, some appear to have the triangular profile of the Mississippian to Penn. Trigonoglossa.  The do appear to be Bracs.

[CMD]

Thanks, Lithophylic. Knowing their brachiopods is good enough for me. I do remember reading somewhere years ago that they are Ordovician in age, and where you find them, Newport Co., RI and the Fall River area of Ma. In Pennsylvanian age conglomorate. But that's all I have, know of no written descriptions anywhere....

[Havenhunter]

Living here along the Chesapeake Bay I'm rather fond of bi-valves myself. Especially the ones you can throw into a pot! 
This fossil bi-valve was found along a riverbank near Hunt, TX by my husband when he was a lad. It's about the size of a large quahog. Thought you might enjoy these.

[CMD]

Nice fossil, Deb! Thanks for sharing. I live in the quahog capital of the world, so it's unfortunate I'm not as fond of today's bivalves as you are   If given a choice, on the other hand, my wife will clam or quahog all day over hunting artifacts. Of course, once in a real blue moon, artifacts come up with the clams hmy:

[Havenhunter]

CMD wrote:

Nice fossil, Deb! Thanks for sharing. I live in the quahog capital of the world, so it's unfortunate I'm not as fond of today's bivalves as you are   If given a choice, on the other hand, my wife will clam or quahog all day over hunting artifacts. Of course, once in a real blue moon, artifacts come up with the clams :

I prefer oysters myself, and each River and bay oysters have their own distinct flavors.
I've found some awesome oyster shell fossils too. They are charcoal gray -and- heavy from the sediment they've absorbed, much like a fossil shark tooth.

[CMD]

[QUOTE]Havenhunter wrote:

Nice fossil, Deb! Thanks for sharing. I live in the quahog capital of the world, so it's unfortunate I'm not as fond of today's bivalves as you are   If given a choice, on the other hand, my wife will clam or quahog all day over hunting artifacts. Of course, once in a real blue moon, artifacts come up with the clams :

I prefer oysters myself, and each River and bay oysters have their own distinct flavors.
I've found some awesome oyster shell fossils too. They are charcoal gray -and- heavy from the sediment they've absorbed, much like a fossil shark tooth.
  No oyster fossils here, but I have found huge oysters in plowed up refuse pits at campsites. The natives loved shellfish, the bays were healthier, and the shellfish could be huge. I've posted this here once before. A quahog from the Providence River, which is actually uppermost Narragansett Bay, where shellfishing has been prohibited for decades. My wife brought this home one day. I counted the annual growth rings last year and I remember it's was close to 200. Actually, I think I deduced it had been "born" in the 1830's....

[Havenhunter]

That's one huge quahog! Here in VA folks prefer their clams smaller, cut into strips, -and- fried. Yummo!

[painshill]

Havenhunter wrote:

Living here along the Chesapeake Bay I'm rather fond of bi-valves myself. Especially the ones you can throw into a pot! 
This fossil bi-valve was found along a riverbank near Hunt, TX by my husband when he was a lad. It's about the size of a large quahog. Thought you might enjoy these.

  That's a whopper Deb... it's a "heart clam". What you have is an internal mould of the shell which makes identification more troublesome but it's probably Protocardia texana, from the Lower Cretaceous.

[Havenhunter]

Thanks, Roger. I always admired this fossil. My husband recalls the bank of the river riddled with so many fossils that folks would toss them into the river with little regard to what they were. Makes me cringe.