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Showing results for tags 'bactrites'.
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I found this at the Lost Creek Dam site at Jacksboro Texas. It is the Finis Shale Member of the Graham Formatoion in the Upper Pennsylvanian Sub-period. I don't often find the apical end of any nautiloids so I was thinking it could help with the ID. There is a dark spot on the oral end that may or may not be the siphuncle, it is not clear. I thought it may be a Bactrites but it would be one without the hemispherical apex and constriction you see on some. It also has a cameral ratio higher than some Bartrites at around 3. I don't know what the black dots are.
Although the most pieces of my collection are goniatites, I am more than happy to add other Devonian cephalopods to my collection from time to time. On my last field trip for devonian cephalopods I splitted a few nodules and some of them had a few uncommon fossils in them: Bactrites I rarely find decent fragments of them, but those few were looking promising. Bactrites, although they look like an orthocone are in fact straight Ammonoids and not a Nautiloid. the septas start to be slightly ondulated, but most important they have a ventral siphuncle, a typical trait of an Ammonoid. the first nodule had a fragment sticking out, and when I split the nodule another one was found inside. I kept both parts of the nodule and prepped the one inside and on top After prepping them I found out that neither of those were complete, but the were decent in size and well preserved. The second nodule on the other hand hand was much better, a piece of the Bactrites was sticking out from both ends of the nodule, so I new I had a complete specimen. The prepping was relatively hard as different parts of the cone had different forms of preservation, but in the end I got the whole specimen out of the matrix and is my best Bactrites until now. enjoythe pictures: 1st nodule with the specimen inside: after prepp: After prep with the top of the nodule containing an other fragment. prepp on the 2nd nodule: after prepp, with the different kinds of preservation visible: and the whole lot:
Past weekend we had a "sunny" field trip to my usual hunting spot with the "LITHOS" geology club. We spent the whole day searching the late Devonian shales and nodules for al kind of fossils, brachiopods, crinoids, cephalopods, corals,... We did find the usual pyritised cephalopods ( manticoceras sp, tornoceras sp. and bactrites sp. ) but to me my biggest prize was when I hit a layer with a lot of goniatite anaptichy enjoy the pictures :