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I found this rock a few years ago and have been wondering about the fossils in it ever since. At first I thought that they where some kind of fish remains, but upon further inspection I am beginning to think that they may be bits of either pterosaur or bird bone. But I really don't know. This rock was found in North Texas in the Upper Coniacian stage of the Austin Chalk Formation. The member of this formation in which I found these fossils is extremely scarce in any vertebrate fossils, with most of the them coming from a more blue/gray toned member of the Austin Chalk which I believe lies underneath this member. In fact, if these are vertebrate fossils then they would be the first and only ones that I have found to date. Aside from vertebrate fossils, the only other thing that I thought that these could be were bits of the hinge of an Inoceramid oyster, which I have found. The last attached photo is of a hinge that I found recently only about 1 mile away from where I found this rock. However, there are a few problems with this theory, the first being the lack of any prismatic (calcitic) crystals being visible in any of the pieces, which there would be if these fossils really were cross section bits of an Inocermid hinge. The prismatic crystals are clearly visible in the cross section view of my Inoceramid hinge. Second, even if I am just not seeing the prismatic crystals, the piece pictured in F7 appears to me to be hollow with a thin, bony looking wall. It is this feature that first got me thinking that these could be bone bits from a pterosaur or a bird. The only thing that makes me rethink that theory is the fact that the larger piece pictured in F2-F3 is completely filled in on the inside and even has something sticking up in the center of it, pictured specifically in F3. But I also do not know for sure whether these two pieces are actually related at all. Compare my fossils with this TFF article about a possible pterosaur bone from the TXI quarry in Midlothian, Texas, which is in the Upper Turonian Atco Formation: And third, at the broken end of the piece pictured specifically in F5 and F6, I see what I perceive as stepped layers where some of it flaked off. That is good evidence against it being an Inoceramid hinge, because the prismatic crystals would be running parallel with an Inoceramid hinge's length, not running perpendicular to it. And as the steppes go down, it seems to show layers of more reddish material, which is also something that I have never seen from an inoceramid shell. There are four main pieces in this rock (which are presumably related) that I am inquiring about, which are pictured in F1-F9. But there are other pieces in this rock that might be related to them, pictured in F10-F12. I also have a few other pieces in this rock that I am pretty sure are not related to the others, pictured in F13 and F14 . F13 is something that I have seen before, but I still do not know what it is, and F14 looks kind of like the shell of a very small urchin, but I really have no idea. The rock its self is 16 cm long. The largest of the 4 main pieces is pictured in F2, F3 and F13 and is 14½ mm in diameter and has 5 mm of it visible above the rock, plus the part of it sticking up in the center. The second largest piece pictured in F4-F7 is 9 mm in diameter and 6 mm in length. The third largest piece pictured in F8 is 5 mm long. And the smallest piece which is right next to the second largest piece is pictured in F4, F9 and is 5 mm long. There are many bits and pieces in this rock that I just can't take pictures of because this post would be 45 pages long. If photos or information apart from what I have already given is needed then I would be happy to give it. I could be way out there and totally off, so I appreciate any help/correction that I get. I am more of an ammonite guy and I don't really know that much at all about vertebrates. Even if these are nothing, I will have learned something. F1 F2