matthew textor Posted March 19, 2008 Share Posted March 19, 2008 Hi this is matt does anybody know what the name of this ammonite is? here is a photo Link to comment Share on other sites More sharing options...
Shuko Posted March 20, 2008 Share Posted March 20, 2008 Hard for me to tell, what with the low F-number setting of your camera. If we could bring the rest of the image into focus, maybe we could see the divisions a little better. Link to comment Share on other sites More sharing options...
Gatorman Posted March 20, 2008 Share Posted March 20, 2008 For ammonites it is very important to get very clear pictures of the suture pattern of the ammonite otherwise positive id is nearly impossible. Link to comment Share on other sites More sharing options...
Mike Murphy Posted March 20, 2008 Share Posted March 20, 2008 Hi, Matt! The subevolute shell with flat flanks and falcate rib pattern all indicate that the ammonite is probably Harpoceras (probably Harpoceras falciferum). If the suture pattern were readily visible, it would easier to confirm the identity. You did not mention the age or locality. Harpoceras falciferum is a key zone fossil of the Toarcian (uppermost stage) of the Lower Jurassic. By the preservation, I would guess that it may be from the Toarcian of the Calvados, France region. Regards, Mike Link to comment Share on other sites More sharing options...
milou115 Posted March 21, 2008 Share Posted March 21, 2008 Hi ! I agree with Mark I would have said Harpoceras but I am not sure tell us where does it come from and its age ! See you ! Mil' Link to comment Share on other sites More sharing options...
Members geofossil Posted March 21, 2008 Members Share Posted March 21, 2008 I've collected dozens of species of Jurassic ammonites and no way of telling 'who is who' except from the sutures. Harpoceras looks no more like the photo than a dozen other genera or species I could post photos of. The similar volute shape and ribbing is present in many genera and is subject to erosion. One can only I.D the specimens from the sutures under the ribbing. Below are all diiferent genera (there's many more) from the Toarcian from Calvados. If the unknown specimen is some other stage or location....add another few dozen genera. Specimens of several genera can look more like eachother in outward appearance than 2 specimens of the same genus. Link to comment Share on other sites More sharing options...
milou115 Posted March 23, 2008 Share Posted March 23, 2008 Hi Geofossil ! What you say is very interesting and I think that the sutures can help a lot but it is very hard to use it to know what is the specie of your ammnite, I think that it is very useful to know the familly or genus, but I don't use it so much. In france few scientists are on the forums and have explained that the best way of knowing the ammonites is to collect them directly in the outcrops knowing perfectly where you've picked it. Then you have to count the number of layers and to write what you have found in each layer then you can know which layer coressponds to which zone in a geological stage, then it is much easier to specify your founds. It is called in french 'un levé de coupe' maybe in english study of a cut...If you want more informations I can tray to translate the topic I hope that my english is understandable, and that I haven't been rude with you Geofossil it is hard to explain what I want See you Mil' Link to comment Share on other sites More sharing options...
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