Arkansasgal Posted July 26, 2019 Share Posted July 26, 2019 Hi, this is my first post, very new to fossil/mineral collecting. Does anyone recognize this portion of what I believe to be a fossil? Pic 1 is what I am calling the top. pic 2 is a close up of an interesting portion of the top. Pic 3 is where the top and bottom wrap around the side to meet each other at some kind of a "V". Pic 4 is what I am calling the bottom. My in-laws are building a house in North Arkansas, I found this in the excavation. I have already identified coral, stromatolites, Shells in other rocks found in the same piles. The main minerals found are quartzite, chert, red sandstone, red clay, calcites, iron, zinc. The area they are found appears to straddles these two regions according to Arkansas geological maps. The house is being built on the top of a large hill: https://www.geology.arkansas.gov/docs/pdf/geology/Collecting-Fossils-in-Arkansas.pdf The Salem Plateau: contains the oldest rock present and is made up of dolostone, limestone and sandstone of Ordovician age. Algal structures called stromatolites, corals, brachiopods, bryozoa, crinoids, gastropods, and some cephalopods are the fossils most commonly found in the limestone and dolostone. Trilobite fragments are less common but are present in these strata. The St. Peter Sandstone contains the vertical trace fossil Skolithos. Silurian and Devonian strata are limited in their outcrop area. Silurian limestones contain crinoids, trilobite fragments, and small algal mounds. Devonian strata are usually unfossiliferous. The Springfield Plateau: is made up of limestone, sandstone, shale, and chert from the Mississippian Period. Corals, bryozoa, brachiopods, crinoids, bivalves, cephalopod, and gastropods are common in these rock types. Trilobite fragments are less common but are present in these rock types as well. Echinoid fragments are present in the Boone Formation. Starfish and bivalve resting traces called Asteriacites and Lockeia respectively, and worm trails are common at certain localities in the Batesville Sandstone Link to comment Share on other sites More sharing options...
caldigger Posted July 26, 2019 Share Posted July 26, 2019 Your pictures don't seem to open. Are you posting directly to this thread? Link to comment Share on other sites More sharing options...
Arkansasgal Posted July 26, 2019 Author Share Posted July 26, 2019 Thank you so much for letting me know! Let me try again Link to comment Share on other sites More sharing options...
Rockwood Posted July 26, 2019 Share Posted July 26, 2019 Iron rich concretion. 1 Link to comment Share on other sites More sharing options...
abyssunder Posted July 26, 2019 Share Posted July 26, 2019 (edited) Pictures have not enough details for me, so I can give just a guess that the specimen may have some characteristics of the Tripolitic chert. I could be wrong. Link " The Lower Mississippian (Osagean) Boone Formation is defined as a succession of chertbearing limestones deposited by third order transgression-regression in a carbonate ramp setting. The Boone carbonate succession, which exceeds thicknesses of 300 feet, is exposed in the tristate region of Arkansas, Missouri, and Oklahoma forming the Springfield Plateau. In northwest Arkansas and southwest Missouri, Boone outcrops contain up to 60-70% chert, which occur as penecontemporaneous, later diagenetic, or tripolitic chert. Although the ample chert content is easily recognized in the Lower Mississippian (Osagean) Boone Formation, certain occurrences of chert, in particular tripolitic chert, are not fully understood. The occurrence of tripolitic chert in the Boone Formation is enigmatic based on the variety of models proposed for the source of chertification, mode of occurrence, and diagenetic history. Several models have been proposed to explain the origin of tripolitic chert, but these hypotheses conflict with one another or lack evidence necessary to completely resolve the problem. " (Just in parenthesis, I'm wondering how that works that a few minutes before logging-in the forum I searched the internet for specimens of Asteriacites. Maybe I'm strange, but my life is stranger than me. Too much coincidences, I can't handle them in a real time. ) Edited July 26, 2019 by abyssunder 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...
Arkansasgal Posted July 27, 2019 Author Share Posted July 27, 2019 Thank you both! I have read a little more on both of your suggestions and pretty sure based on location and hardness of this material ( doesn't stratch with a knife or quartz point) it is a chert nodule that has characteristics of bone, but isnt...I think it was called a psuedofossil? The other chert I found where beautiful pieces of banded chert. Some of them looked like bone as well. 2 Link to comment Share on other sites More sharing options...
abyssunder Posted July 27, 2019 Share Posted July 27, 2019 You are welcome! " 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...
Arkansasgal Posted July 28, 2019 Author Share Posted July 28, 2019 (edited) That is so cool!!! They are in the area below Branson and above Harrison right on the color change, so would that definitely be Springfield plateau? Edited July 28, 2019 by Arkansasgal Error Link to comment Share on other sites More sharing options...
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