PAJim Posted August 23, 2015 Share Posted August 23, 2015 Im curious about Nodules....I know in essence what they are and how they form. I loved those crab nodules that were posted here awhile back. My question is, how can you tell there is something inside them? All the ones I found were a hard as...well...rock, and I couldnt split them, just remove the outer layers. This one I found like it is and it has some crystals in it. Link to comment Share on other sites More sharing options...
Ludwigia Posted August 23, 2015 Share Posted August 23, 2015 (edited) My question is, how can you tell there is something inside them? Put simply: you can't. That said, I'll extrapolate a bit. Nodules, as you probably know, can be found in clay sediments of all ages. A collector needs to have a geological knowledge of the various layers in order to be able to discern whether fossils may be found in them, whether they have metallic or crystalline deposits in the internal cracks brought about through the drying process (septaria), or whether there's nothing in them at all. Sometimes there are little clues on the outside, like part of a claw, or the keel of an ammonite, but that's often not the case. Then you have to rely on experience and judgement. First of all, fossilized ones usually occur in particular layers, so if you're removing them directly from the rock unit, then you have to know where you are. Secondly, depending on the Formation and fossil content, fossilized nodules sometimes have particular outward forms and colors, so experienced collectors can develop a feeling for this and don't need to necessarily bash open every concretion they find. Still, where there's any doubt, the best thing is to just hammer away merrily until you've found something, making sure that you've done it in such a way that all of the pieces can be saved. Then you'll have a bit of work ahead of you at home piecing it back together and prepping it. Edited August 23, 2015 by Ludwigia Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Mike Pocock Posted August 24, 2015 Share Posted August 24, 2015 Hi, Ludwigia is right have a look at the attached these are obvious ones with ammonites in them. Good luck with the hunting. Regards Mike Link to comment Share on other sites More sharing options...
Fossildude19 Posted August 24, 2015 Share Posted August 24, 2015 While bashing concretions/nodules with a hammer works, it often leaves you with chunks that run perpendicular to the fossil bedding plane. Most nodules tend to have flattened sides(top/bottoms?) If so, often the bedding plane(if there is a fossil) is horizontal to the flatter edges. If you are going to use a hammer and chisel, you want to put the nodule on it's side, and try to find the bedding plane that way. Alternately, you might consider prepping some nodules via the Freeze/Thaw method. Might be worthwhile. Basically put - you saok the nodules in water for at least 24 hours. Pop it in the freezer, wet, again, for 24 hours ... then defrost for a day, repeat as neccesary til it pops open. Search the Forum for more info on the freeze/thaw method. Regards, Tim - VETERAN SHALE SPLITTER VFOTM --- APRIL - 2015 IPFOTM -- MAY - 2024 _________________________________________________________________________________ "In every walk with nature one receives far more than he seeks." John Muir ~ ~ ~ ~ ><))))( *> About Me Link to comment Share on other sites More sharing options...
Lmshoemaker Posted August 24, 2015 Share Posted August 24, 2015 Question- does freeze thaw, despite taking longer typically produce better results? I had a few nodules with conulariids which splintered easily, and was wondering if freezing may be better than cracking them with a hammer. Link to comment Share on other sites More sharing options...
Auspex Posted August 24, 2015 Share Posted August 24, 2015 Freeze/thaw takes longer, but is less likely to produce gravel. "There has been an alarming increase in the number of things I know nothing about." - Ashleigh Ellwood Brilliant “Try to learn something about everything and everything about something.” - Thomas Henry Huxley >Paleontology is an evolving science. >May your wonders never cease! Link to comment Share on other sites More sharing options...
Ludwigia Posted August 24, 2015 Share Posted August 24, 2015 I'd forgotten to mention the freeze/thaw method, which as the above members have stated, can bring good results. Greetings from the Lake of Constance. Roger http://www.steinkern.de/ Link to comment Share on other sites More sharing options...
Lmshoemaker Posted August 24, 2015 Share Posted August 24, 2015 Freeze/thaw takes longer, but is less likely to produce gravel. Heh, that's a lovely way of putting it. Next time I'll try freeze thaw then. Link to comment Share on other sites More sharing options...
Mike Pocock Posted August 25, 2015 Share Posted August 25, 2015 Hi I have never heard of the freeze / thaw method will it work with the limestone that Whitby ammonites are in such as the ones on this post, when you hit a Whitby ammonite typically you will shatter 3 out of 5 beyond repair, so I will give the freeze /thaw a go if it will work. Regards Mike Link to comment Share on other sites More sharing options...
RJB Posted August 25, 2015 Share Posted August 25, 2015 Hey PAJim. Ive spent over 20 years finding concretions. Ive wacked them open with sledge hammers and chisles amd ruined quite a few in the first years, but now can usualy tell if there is a crab inside and how its situated in the rock and can simply start prepping, but there are some that are soooooo round that its just a guess. Also, even in the same layer you can get concretions that have nothing in them and everything from a crab to a piece of clam or a piece of wood. I call those BFN's. Big Fat Nothin's. Ha! Anyways, good luck hunting. RB Link to comment Share on other sites More sharing options...
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