VRoche Posted August 8, 2019 Share Posted August 8, 2019 Just wondering if this is a fossil and of it is, what do you think it might be? Sorry I didn't have a ruler when taking pics. My thumb is on the pics and it's about an inch or a little less across. This was found in a limestone riverbed near Justin, Texas (North Central Texas). We have found many other smaller marine fossils (actually casts I think - I am not an expert by any means) that I am pretty sure are from the Cretaceous Period in the same area. I have more pictures that are higher resolution, but I can't upload them here due to the size restrictions. Thanks in advance for any info or ideas that you might have. Link to comment Share on other sites More sharing options...
Rayminazzi Posted August 8, 2019 Share Posted August 8, 2019 It might be a chunk of ammonite, there is a whole ammonite on the rock as well, right hand side of the first picture. Can't help with I'd though Link to comment Share on other sites More sharing options...
grandpa Posted August 8, 2019 Share Posted August 8, 2019 First, welcome to the forum. Second, I believe what we are looking at is an imprint of an inoceramid clam. I too noticed what I find the more interesting part of the piece, the whole ammonite. 2 Link to comment Share on other sites More sharing options...
Heteromorph Posted August 8, 2019 Share Posted August 8, 2019 Yep, inoceramid clam. If this is the Duck Creek Formation, the ammonite is probably Mortoniceras. 4 Link to comment Share on other sites More sharing options...
VRoche Posted August 9, 2019 Author Share Posted August 9, 2019 Thank you for all of that great information! I find those ammonites all of the time if they are the ones that look like the attached pic. I just don't know how to get the bigger ones out of the limestone to bring them home. I also don't know how to really clean the ones that I have found. Also, are these considered casts of the actual fossil and not really a fossil? Link to comment Share on other sites More sharing options...
VRoche Posted August 9, 2019 Author Share Posted August 9, 2019 Here are pics of other things that I have found. Lots of oysters and small shells. A few of the spiral shells and sometimes urchins (I love those)! Not sure if the cylinder shaped thing is a fossil or just a funny shaped rock? I'm obviously not an expert... Link to comment Share on other sites More sharing options...
VRoche Posted August 9, 2019 Author Share Posted August 9, 2019 This is great! I am reading up on all of the information that you all have given me so far. I had never heard about the Duck Creek formation. I also didn't know what kind of ammonites I have been finding so that is interesting to find out. I have been looking at pics of imprints of inoceramid clams and I do see where that might be what I have. Amazing that you all can figure that out so quickly! Link to comment Share on other sites More sharing options...
Heteromorph Posted August 9, 2019 Share Posted August 9, 2019 Alright, with all these Oxys, I need to revise my initial IDs. (I’m certainly no expert, just learning as I go.) For clarification, all the ammonites you posted are steinkerns, i.e. the shell was filled with mud, the mud lithified, the shell dissolved away, and you are left with the casts molds. The original shell material is gone. That goes for your gastropod too. Oxytropidoceras occurs in the extremely basal Duck Creek (Washita Group), down through the Kiamichi, Goodland, and Walnut Clay formations (Fredericksburg group, see also Refs. 1, 2). From my limited experience, your finds look more like material from the Goodland Formation, which is age equivalent to the Comanche Peak Clay and Edwards formations to the south of Parker County. It is a bit older than the Duck Creek, but still Albian in age. Assuming this is the Goodland, specifically: Pic 10 is an oyster, Texigryphaea spp. The fossil just after that is a heavily worn oyster, hard to say beyond that. Pic 13 is a worn clam, Lima wacoensis (Ref. 3) Pic 14 is a gastropod steinkern, perhaps Tylostoma sp. Picture isn’t great, but your spatangoid is probably Pliotoxaster whitei (Ref 4). Pic 16, Burrow cast. Perhaps most pertinent is that, after further review, I am pretty sure that the original mold you posted is not an inoceramid but is the ventrolateral mold of another Oxy. The mold of the extremely high keel can be seen, along with the slanted ribs. It also looks very similar to this Oxy ventrolateral mold posted on TFF. There are many Oxy species in the four formations I mentioned, so narrowing it to species is difficult for me. So instead of that, here are some other links that I have found helpful on this topic: Cretaceous Fossils.com The website has been defunct since 2007, and thus some of the info is outdated, but it is still has tons of informative content. Look in the ammonite section for the pages on Oxytropidoceras. https://www.txfossils.com/ Need help identify Texas Fossil Attention Texas experts! What is growing on my ammonite? If you want to be sure about what formation you are in, I would look up where you found these in the apps Mancos, Rockd, or Pocket Texas Geology. Also, TFF’s search feature is highly customizable and versatile, which has greatly helped me sift through the thousands of threads to what I want to find. I'm sure it will serve you well on your future research endeavors 20 hours ago, VRoche said: Oxy Mortonicerid ammonite? The keel looks pretty high, however, so it may just be a different Oxy species. It looks encrusted with oyster stuff. Oxy Oxy 4 Link to comment Share on other sites More sharing options...
DPS Ammonite Posted August 9, 2019 Share Posted August 9, 2019 10 minutes ago, Heteromorph said: For clarification, all the ammonites you posted are steinkerns, i.e. the shell was filled with mud, the mud lithified, the shell dissolved away (in that order?), and you are left with the casts You are actually left with internal molds not casts. A mold is made against the original shell. A cast would be a reproduction in a different material of the original ammonite shell. 2 My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
Heteromorph Posted August 9, 2019 Share Posted August 9, 2019 2 minutes ago, DPS Ammonite said: You are actually left with internal molds not casts. A mold is made against the original shell. A cast would be a reproduction in a different material of the original ammonite shell. I always get that backwards, for some reason. 1 Link to comment Share on other sites More sharing options...
VRoche Posted August 9, 2019 Author Share Posted August 9, 2019 Wow, thank you so much for taking the time to look at all of my pics and figure out all of those things! I also appreciate the links so I can research more. Thanks so very much! Just to give you a better idea of where I find these, it's about 9 or 10 miles NE of Justin, TX, in an old limestone stream bed. I would guess that entire area has limestone a few feet below the farmland. I will check out the links that you sent to me and see if I can find the exact place. Thanks again! Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted August 9, 2019 Share Posted August 9, 2019 12 hours ago, DPS Ammonite said: 12 hours ago, Heteromorph said: For clarification, all the ammonites you posted are steinkerns, i.e. the shell was filled with mud, the mud lithified, the shell dissolved away (in that order?), and you are left with the casts You are actually left with internal molds not casts. A mold is made against the original shell. A cast would be a reproduction in a different material of the original ammonite shell. There's actually four different possibilities. A cast can be created by a mold of the original which can then create a cast which creates a new mold, so that the material is actually third-hand, so to speak. It's freaky hard to wrap your head around until you see a 3D simulation. I tried to find the one I saw on YouTube but haven't found it. It may help if you think of an impression as an external cast, or it may just make it more confusing. Awesome finds, by the way. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
VRoche Posted August 9, 2019 Author Share Posted August 9, 2019 12 hours ago, Heteromorph said: It also looks very similar to this Oxy ventrolateral mold posted on TFF. That pic looks almost exactly like what I found. Thank you for solving this mystery for me! Link to comment Share on other sites More sharing options...
DPS Ammonite Posted August 9, 2019 Share Posted August 9, 2019 7 minutes ago, Mark Kmiecik said: “A cast can be created by a mold of the original which can then create a cast which creates a new mold.” I am not sure that I follow. Yes, a cast is created against a mold. The space between the internal and external molds of an ammonite can be filled to create a cast of the ammonite. A cast of the ammonite can be used to create new molds. However, a cast cannot directly create a new cast. 18 minutes ago, Mark Kmiecik said: It may help if you think of an impression as an external cast, An impression of the original fossil body (or cast of it) is an interior or exterior mold and not a cast. An impression of an exterior mold could create an exterior cast. Confused yet? My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
grandpa Posted August 9, 2019 Share Posted August 9, 2019 29 minutes ago, VRoche said: Just to give you a better idea of where I find these, it's about 9 or 10 miles NE of Justin, TX, in an old limestone stream bed. If you want to find out what age you're searching in at any location in Texas, down to the Member, use the Texas geological interactive map at https://txpub.usgs.gov/txgeology/ Click on "Rock Units" and "Members" in the menu to the left of the map and use your mouse wheel to zoom in on the area in which you are hunting. Link to comment Share on other sites More sharing options...
Ludwigia Posted August 9, 2019 Share Posted August 9, 2019 18 hours ago, VRoche said: I just don't know how to get the bigger ones out of the limestone to bring them home. I also don't know how to really clean the ones that I have found. Here is some good information on how to get fossils out of their matrix, in your case, the limestone. And you can find loads of information on how to clean your fossils (or prepare them as we call the process) here. 2 Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
garyc Posted August 9, 2019 Share Posted August 9, 2019 52 minutes ago, Mark Kmiecik said: There's actually four different possibilities. A cast can be created by a mold of the original which can then create a cast which creates a new mold, so that the material is actually third-hand, so to speak. It's freaky hard to wrap your head around until you see a 3D simulation. I tried to find the one I saw on YouTube but haven't found it. It may help if you think of an impression as an external cast, or it may just make it more confusing. Awesome finds, by the way. We’ll never reeeeally know until we find out whether the chicken or the egg came first Link to comment Share on other sites More sharing options...
grandpa Posted August 9, 2019 Share Posted August 9, 2019 14 minutes ago, garyc said: We’ll never reeeeally know until we find out whether the chicken or the egg came first Oh, I think we know the answer to that one. The genetic blueprint for a chicken had to take place in the embrio, not in an already defined animal that would then morf into a chicken. Thus, the egg with the genetic blueprint for a chicken HAD to come first - right? Link to comment Share on other sites More sharing options...
grandpa Posted August 9, 2019 Share Posted August 9, 2019 1 hour ago, DPS Ammonite said: I am not sure that I follow. Yes, a cast is created against a mold. The space between the internal and external molds of an ammonite can be filled to create a cast of the ammonite. A cast of the ammonite can be used to create new molds. However, a cast cannot directly create a new cast. An impression of the original fossil body (or cast of it) is an interior or exterior mold and not a cast. An impression of an exterior mold could create an exterior cast. Confused yet? Don't go casting mold on my steinkerns! May I add to the confusion? Please see: https://sciencing.com/mold-cast-fossils-6556194.html https://www.prehistoriclife.xyz/fossil-collectors/casts-and-molds.html Link to comment Share on other sites More sharing options...
DPS Ammonite Posted August 9, 2019 Share Posted August 9, 2019 4 minutes ago, grandpa said: Don't go casting mold on my steinkerns! May I add to the confusion? Please see: https://sciencing.com/mold-cast-fossils-6556194.html https://www.prehistoriclife.xyz/fossil-collectors/casts-and-molds.html Keep your dirty steinkerns out of the conversation. My goal is to leave no stone or fossil unturned. See my Arizona Paleontology Guide link The best single resource for Arizona paleontology anywhere. Link to comment Share on other sites More sharing options...
VRoche Posted August 12, 2019 Author Share Posted August 12, 2019 Not only are you all knowledgeable, you are entertaining too! Now let's see if I have this right: A fossil is a fossil A mold is a fossil A cast is a fossil A fossil can become a cast A fossil can become a mold A cast can become a mold A mold can become a cast :-) Link to comment Share on other sites More sharing options...
Sberebit Posted August 14, 2019 Share Posted August 14, 2019 Link to comment Share on other sites More sharing options...
Mark Kmiecik Posted August 14, 2019 Share Posted August 14, 2019 On 8/12/2019 at 4:35 PM, VRoche said: Not only are you all knowledgeable, you are entertaining too! Now let's see if I have this right: A fossil is a fossil A mold is a fossil A cast is a fossil A fossil can become a cast A fossil can become a mold A cast can become a mold A mold can become a cast :-) It's like playing with Legos and PlayDoh. Then you let the PlayDoh dry and push more PlayDoh onto the dry PlayDoh after making the original Legos disappear by melting them away with your magic dissolving wand and then rinsing and repeating and adding PlayDoh and sticking that onto another Lego of a different shape and color. It's really quite simple. Mark. Fossil hunting is easy -- they don't run away when you shoot at them! Link to comment Share on other sites More sharing options...
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