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El_Hueso

How does one determine if a nodule has fossils in it?

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El_Hueso

Howdy all,

 

I tried searching for answers on the search bar, but couldn't find anything, so I'm hoping someone can help me out.

 

I was going through the fossil prep section and noticed that many people seem to start off with a large nodule and remove all the matrix to reveal the fossil hidden inside. My question is, how does one (a seller, or person out on a fossil hunt) even determine that a big hunk of nodule has a fossil inside if there are no immediate visible indications of a fossil from the outside?

 

Once again thanks.

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Mark Kmiecik
51 minutes ago, El_Hueso said:

Howdy all,

 

I tried searching for answers on the search bar, but couldn't find anything, so I'm hoping someone can help me out.

 

I was going through the fossil prep section and noticed that many people seem to start off with a large nodule and remove all the matrix to reveal the fossil hidden inside. My question is, how does one (a seller, or person out on a fossil hunt) even determine that a big hunk of nodule has a fossil inside if there are no immediate visible indications of a fossil from the outside?

 

Once again thanks.

Portable x-ray machine. The pocket-sized hand-held battery-powered ones are only 37,500 dollars (batteries not included, available separately at 275 dollars each, takes four).

 

Just kidding! :D In many cases there's a clue on the outside of the concretion. If you've looked at the fossil crab prep threads you'll know what I mean. In other cases, like Mazon Creek concretions you can't tell most of the time. You just have to freeze and thaw them until they crack open. Some that contain ammonites also have no visible clues. You just hammer them until they crack and maybe there's a fossil inside, but you have to know where to hit them so they crack in the correct plane and not across the fossil. In many such cases the concretion is slightly flat and the hammering is done along the "edge". It becomes easier with experience to tell where in the concretion the fossil would most likely lie and the ideal spot to apply the shock of the hammer blow. Sometimes it is more of an art than a science. Some concretions are impossible to crack open without damaging the fossil because of the shape of the fossil, like those 3D crabs. Then one starts by using "power" tools to remove rock from above the fossil until a small part of it can be seen and then the matrix is carefully pulverized spreading outwards and downwards from that spot until the entire specimen is exposed. Sometimes the ventral side of a fossil is exposed accidentally, but sometimes it is done with intent. As far as finding them goes, again it's experience that makes all the difference. Rocks stop looking all the same once you've been collecting for a while. You quickly learn the right shape, color, texture or whatever else composes what you're collecting. When you start out and don't have someone experienced to point out the (sometimes subtle) difference you will have to haul a lot of extra weight before you learn what to avoid. There are countless quantities of different fossils and states of preservation and new ones being found frequently enough that no one person knows all the details, but the general locations, types and methods are fairly easy to learn and will suffice in most cases. Just hang around here and ask questions and read as much as you can. Hint: if you read about something that catches your eye the time will fly and you will learn.

 

P.S. -- Some fossils, like trilobites have like 50,000 different species, and that's only the ones we know about. Choose wisely.

 

EDIT: Another thing -- concretions are like splitting shale layers to find fossils. You don't know if there's anything between the layers until you split them, so sometimes it's just a crapshoot. Learning to tell the difference among igneous, metamorphic and sedimentary rock is the first step as most fossils are found in sedimentary stone. If you already knew this, please forgive me for stating it.

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El_Hueso

I cannot thank you enough for taking your time to give such a thoughtful and detail reply to my post. You were extremely informative in answering my question.

 

I guess my next step would be to look around at posts from other folks here in Texas who hunt for invertebrate fossils and see if I can find any topics that relate to them uncovering nodules.

 

Im trying my best not to get ahead of myself though. I’ve been so excited ever since finding this forum that it’s ignited my interest in this. Now I just want to soak up all the info I can and try to get as active as my work schedule/house keeping life will allow me. I can’t decided if I want to go on a gulf coast shark tooth hunting trip, head out to whiskey bridge, or head up to glen rose for clam shells. Likewise I’m trying my best to restrain myself from using up an entire paycheck for prepping equipment, more dremel bits, hammers and other tools... I need to take baby steps lol

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Mark Kmiecik

Texas is like Illinois in that you don't have to go out-of-state to find a huge variety of fossils. And Texas is much larger than Illinois, so there's more and bigger, (because, you know, Texas) to be found near to you. Have fun. Post photos of your finds. If you find something you can't ID, post it in the ID thread.

 

Good luck and happy hunting.

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Nirang
28 minutes ago, Mark Kmiecik said:

Texas is like Illinois in that you don't have to go out-of-state to find a huge variety of fossils. And Texas is much larger than Illinois, so there's more and bigger, (because, you know, Texas) to be found near to you. Have fun. Post photos of your finds. If you find something you can't ID, post it in the ID thread.

 

Good luck and happy hunting.

I could not agree more on that reaponse Mark ...and about Texas....One of the GOOD aspects about living in Texas :) I have been fortunate enough to not have to have a real job the past year or so and a couple years ago my somehow forgotten passion was rekindled with a VENGENCE!!! Good timing. It's pretty much all I think about and do lol.....There are rocks to find pretty much EVERYWHERE here and I search pretty much daily so if you need ideas El Hueso on where to go i am

fairly versed around central Texas, especially Nice are New Braunfels/Canyon Lake, Just moved to Lockhart and oh my gawd! It's amazing and Indian artifacts WVERYWHERE   ...I'm not real versed yet in names and vocabulary but I have learned the hard way like you said....so much weight carried around LOL and I dunno how many thousands of rocks I just moved lol...........texture is a big indicator for me, as well as weight distribution and type of rock like you say. Always had a knack for repeating patterns and the like. Good times!

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grandpa

Nirang, those are some nice Exogyra you have put together.  Especially of interest to me is the one in the second row, far left side - the "spiky" one.  I believe that this is an

Exogyra costata spinifera.  That is an indicator fossil that you are in the Upper Cretaceous, Navarro Formation.  Nice find.  Keep looking, you should find other interesting fossils in the Navarro.

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Nirang

Thanks! I had found the sweet spot(well several) all of those came from 15 min session ......also several construction sites with huge mountains of dug out with TONS of the giants I have proabbaly 30 of mixed variety, mainly Exogera Ponderosa if my research was correct. I do really like he spiny ones....you’d like this one I’ll try to take pic it’s with BOTH SHELL halves and has beautiful detail spines....I dug him out of the ground still together ......found this yesterday on the property where I live....fish? Leaf? What do you think? I will post in the ID as well but you get first dibs lol

D151AD2D-60A0-4B2B-845C-6EE0B34E6544.jpeg

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grandpa

OK, so I'm clueless :zzzzscratchchin:, but it IS an interesting specimen.  Hope someone can  be more helpful.

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