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I've got an interesting fossil here and I'm wondering if it is a tooth, and if so, from what animal? It was found on the banks of the Mississippi River around St. Louis, Missouri, thus I have no clue what formation it is from as it could have washed out from anywhere upstream. The folds on one end remind me of dentine folds, and it is in line with being part of the grey, straight, line fossil on the edge of the piece. Also, the foveae around the alleged dentine reminds me of cartilage. Just north of St. Louis, MO, there is a quarry on the Illinois side where an anthrodire tooth was found in Cedar Valley Limestone (limestone & sandstone) -- this is what sparked the thought of it being a tooth. The white rock is chalky & soft, but doesn't seem to react much at all when I scraped dust into vinegar. The brown material seems ferrous & sandy. The grey part is translucent when a light is pressed against it. Sorry, I am not great at rock ID yet. Centimeter ruler is in brown, the grey grid is 1 in squares with 1/4in dots. Some of the high-magnification photos are through a 10x loupe connected to a phone. Let me know what kind of photos would help with ID -- mark particular points you want addition photos from and I'll do my best to get them promptly.

Hi, two weeks ago i found my first meg tooth on a site (Serravalllian) where all the other ones were found with their enamel and a grey or greenish colour. In brown clay. This one is light brown and its enamel seems to have vanished. Except in small parts where it isn't shiny. I found it in a darker brown level that seemed to be Iron rich. When i tried to prep it a bit snapped away and the surface in contact with the tooth appeared dark, shiny. Smoother than the matrix. The matrix that is still on the tooth is very, very hard. I wondered if the lack of enamel is only the result of weather or if the ferruginous matrix is involved.

Advanced technology sheds new light on evolution of teeth by Uppsala University, PhysOrg, July 9, 2020 https://phys.org/news/2020-07-advanced-technology-evolution-teeth.html Scientists trace the origin of our teeth from the most primitive jawed fish, European Synchrotron Radiation Facility, July 9, 2020 https://www.sciencedaily.com/releases/2020/07/200709141606.htm https://www.eurekalert.org/pub_releases/2020-07/uu-ats070820.php Four hundred million year old fish fossil has earliest example of teeth by Bob Yirka, June 24, 2015 https://phys.org/news/2015-06-million-year-fish-fossil-earliest.html The papers are: Vaskaninova, V., Chen, D., Tafforeau, P., Johanson, Z., Ekrt, B., Blom, H., and Ahlberg, P.E., 2020. Marginal dentition and multiple dermal jawbones as the ancestral condition of jawed vertebrates. Science. 369(6500) pp.211-216. https://science.sciencemag.org/content/369/6500/211 Rücklin, M. and Donoghue, P.C., 2015. Romundina and the evolutionary origin of teeth. Biology Letters, 11(6), p.20150326. https://royalsocietypublishing.org/doi/abs/10.1098/rsbl.2015.0326 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.781.8298&rep=rep1&type=pdf https://research-information.bris.ac.uk/files/55864918/Rucklin_2015.pdf Yours, Paul H.

I have a focus on whale today because I recently obtained a few. This generally leads me to trying to understand and identify my finds. This in turn leads to questions. What is Whale Ivory? When I can not find answers or at least thoughtful discussion elsewhere, thanks for TFF. I found a PDF here: https://www.cites.org/sites/default/files/eng/resources/pub/E-Ivory-guide.pdf Nothing in the above definition of Whale Ivory ever uses the word "Ivory". What exactly is the whale Ivory? Modern Whale tooth -- Is the slightly yellow tip the enamel? Is the Cementum covering the Ivory? What about Fossil whale teeth like this Scaldicetus: The tip enamel is easily seen. Is the outer covering Cementum or Ivory or both?

A very interesting blog, also addresses what can palaeontologists learn from dentine? https://aaronrhleblanc.wordpress.com/2018/01/29/what-are-teeth-made-of-part-2-dentine-and-the-pulp/