Rocksandrocks Posted January 16, 2022 Share Posted January 16, 2022 Hi! I just found this fossil (it’s a fossil right?) in Northwest Arkansas, but haven’t been able to ID it. Anyone know what it is? It’s about two and half inches wide. Thanks! Link to comment Share on other sites More sharing options...
FranzBernhard Posted January 16, 2022 Share Posted January 16, 2022 Welcome to TFF from Austria! I see a fenestelid bryozoan to the lower right of the first pic. But I have absolutely no idea, what the main fossil could be, never seen that pattern before. So I am going to learn something new today . Would you like to give some measurements of the fossil? And to what formation it could belong? Thank you very much! Franz Bernhard 1 2 Link to comment Share on other sites More sharing options...
Sjfriend Posted January 16, 2022 Share Posted January 16, 2022 My first thought is worn coral (but I'm surprised no one said fossil strawberry ) 3 1 Link to comment Share on other sites More sharing options...
FranzBernhard Posted January 16, 2022 Share Posted January 16, 2022 5 minutes ago, Sjfriend said: no one said fossil strawberry No, no, we failed already on that one somewhere . Franz Bernhard 2 1 Link to comment Share on other sites More sharing options...
Rocksandrocks Posted January 16, 2022 Author Share Posted January 16, 2022 Hi! Thanks for responding. The fossil is 2.5 inches at its widest and 2 inches tall. Or, for the Austrians amongst us, 6.35 cm wide and 5.08 cm tall. I’m pretty new to fossil identification. Not sure what “formation” means, but If that is the same as period, I think the area where I found the fossil is either Mississippian or Carboniferous—but I’m not certain. I’m having a bit of a time figuring this out. The rock was found in Rogers, Arkansas. Strawberry fossil! Good one. 1 Link to comment Share on other sites More sharing options...
Lone Hunter Posted January 16, 2022 Share Posted January 16, 2022 The period is referring to time as in age of a formation, to find that look at a geologic map. 1 Link to comment Share on other sites More sharing options...
Rocksandrocks Posted January 16, 2022 Author Share Posted January 16, 2022 Thanks! Very helpful. Here’s what I found… Boone Formation/(Limestone/Chert) Age: Early and Middle Mississippian Period Distribution: Northern Arkansas, Ozark Plateaus; southwestern Missouri and eastern Oklahoma Geology: The Boone Formation consists of gray, fine- to coarse-grained fossiliferous limestone interbedded with chert. Some sections may be predominantly limestone or chert. The cherts are dark in color in the lower part of the sequence and light in the upper part. The quantity of chert varies considerably both vertically and horizontally. The sequence includes an oolite member (Short Creek Member) near the top of the Boone Formation in western exposures and the generally chert-free St. Joe Member at its base. The Boone Formation is well known for dissolutional features, such as sinkholes, caves, and enlarged fissures. Crinoids are the most common fossil found in the formation, but brachiopods, bryozoa, mollusks, corals, shark material, trilobites, conodonts, and others fossils are known. The lower contact of the Boone Formation is considered disconformable in most places, but some workers suggest a conformable lower contact with the Chattanooga Shale; the contact with the St. Joe Member is conformable. The thickness of the Boone Formation is 300 to 350 feet in most of northern Arkansas, but as much as 390 feet has been reported. Link to comment Share on other sites More sharing options...
Lone Hunter Posted January 16, 2022 Share Posted January 16, 2022 Great! If you could also provide measurements then maybe someone can figure this out Link to comment Share on other sites More sharing options...
abyssunder Posted January 16, 2022 Share Posted January 16, 2022 Somehow it looks close to Pleurodictyum or similar coral. 1 1 1 " We are not separate and independent entities, but like links in a chain, and we could not by any means be what we are without those who went before us and showed us the way. " Thomas Mann My Library Link to comment Share on other sites More sharing options...
oyo Posted January 16, 2022 Share Posted January 16, 2022 (edited) + 1 for some kind of coral. Edited January 16, 2022 by oyo Link to comment Share on other sites More sharing options...
Rocksandrocks Posted January 16, 2022 Author Share Posted January 16, 2022 The fossil is 2.5 inches at its widest and 2 inches tall — 6.35 cm wide and 5.08 cm tall. Link to comment Share on other sites More sharing options...
Mahnmut Posted January 16, 2022 Share Posted January 16, 2022 Hi Rocksandrocks, interesting fossil. Is that third texture to the top right, above the bryozoa, a shell impression of some kind? Good of you to include some obscure measure native to Austria called "cm". Best Regards, J Try to learn something about everything and everything about something Thomas Henry Huxley Link to comment Share on other sites More sharing options...
Rocksandrocks Posted January 16, 2022 Author Share Posted January 16, 2022 Hi Mahnmut. That is a third fossil in the top right. Some kind of shell. Not enough there to identify the exact kind. Link to comment Share on other sites More sharing options...
Sjfriend Posted January 17, 2022 Share Posted January 17, 2022 19 hours ago, Rocksandrocks said: Strawberry fossil! Good one. The joke was the forum has had that exact question before lol 1 Link to comment Share on other sites More sharing options...
Rocksandrocks Posted January 17, 2022 Author Share Posted January 17, 2022 Ahhhhh! I see. How often do fossils not get ID’d and remain mystery fossils? Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted January 17, 2022 Share Posted January 17, 2022 10 minutes ago, Rocksandrocks said: Ahhhhh! I see. How often do fossils not get ID’d and remain mystery fossils? It depends on the quality of preservation. If it's worn so the details are gone, identification is possible usually only to genus level. If details are present, genus and species. I thought I'd throw in this chart to get you started with time scale. This is one of the more detailed ones available. If you google it you can find a clearer image. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
Rocksandrocks Posted January 17, 2022 Author Share Posted January 17, 2022 Thank you!! Link to comment Share on other sites More sharing options...
Lone Hunter Posted January 17, 2022 Share Posted January 17, 2022 If you were looking for percentage of fossils that are never ID'd my guess would be about 10% or less. Link to comment Share on other sites More sharing options...
Sjfriend Posted January 17, 2022 Share Posted January 17, 2022 1 hour ago, Rocksandrocks said: Ahhhhh! I see. How often do fossils not get ID’d and remain mystery fossils? Not very many for sure. With good preservation, very good photos and a little time they are at least ID'd to genus most if the time. This is one extremely knowledgeable group of fossil nuts. Link to comment Share on other sites More sharing options...
TqB Posted January 17, 2022 Share Posted January 17, 2022 (edited) I think it's a bryozoan, one of the fenestellids with multiple pore rows such as Polypora. (It's a mould of course.) A Russian one from here that looks the right sort of thing: http://www.lakeneosho.org/Russia/Page16.html#2 Edited January 17, 2022 by TqB 3 2 Tarquin Link to comment Share on other sites More sharing options...
ClearLake Posted January 17, 2022 Share Posted January 17, 2022 I'm with @TqB in that it is a mold of a bryozoan. Here is a snippet off of the Dallas Paleo Society page on Pennsylvanian Bryozoans. Prior to seeing the previous post, I happened on the same genus due to the multiple rows of zooids that are visible on each branch and they are arranged in a regular pattern. The genus Polypora is known from the Mississippian and bioherms containing significant amounts of bryozoans and crinoids are reported from the Boone formation according to a thesis I found online.. 2 Link to comment Share on other sites More sharing options...
Rocksandrocks Posted January 18, 2022 Author Share Posted January 18, 2022 (edited) Very cool! It does look like a Bryozoan! One question….the part of the rock that has the Bryozoan pattern seems to be shaped like a “shell”. It might not be clear in the picture, but there are very distinct demarcations (grooves) between the Bryozoan area and the rest of the rock. But…I just discovered this…the portion of the rock directly to the lower right of the Bryozoan area also has a similar pattern and mirror shape, (circled in the photo) as if it might be the opposite side of of the same “shell” that comprises the main part of the Bryozoan fossil. Would the Bryozoan have been formed on top of a shell? Is that a possibility? Thanks! Edited January 18, 2022 by Rocksandrocks Link to comment Share on other sites More sharing options...
TqB Posted January 18, 2022 Share Posted January 18, 2022 7 hours ago, Rocksandrocks said: Would the Bryozoan have been formed on top of a shell? Fenestellids were free growing fronds of various forms, not encrusters. They had holdfasts which tend to be attached to a hard substrate, including shells. Tarquin Link to comment Share on other sites More sharing options...
Rocksandrocks Posted January 18, 2022 Author Share Posted January 18, 2022 Aha! Thank you!! Link to comment Share on other sites More sharing options...
pefty Posted March 16 Share Posted March 16 Chiming in late to say that this has all the marks of the cystoporate bryozoan Glyptopora, a common enough Boone find. Not all species of Glyptopora have those school-of-fish maculae, but most do. Here's is E. O. Ulrich's drawing: 1 Link to comment Share on other sites More sharing options...
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