Doctor Mud Posted January 20, 2014 Share Posted January 20, 2014 Hi guys, I just started work on this concretion I recently picked up from Glenaffric, New Zealand. The big question is always: Which way is up? Following Jason's guide on his website about concretions from WA: http://www.fossilcrabs.com/aboutus.htm the bottom of the concretion usually has more material. So I think I had the concretion upside down in the right-hand images above. You might also notice a tiny hole in the upper right-hand image - this is on the left of the concretion. I presumed this was a pincer and this might give me another clue to the orientation of the crab. The larger pincer is always the right hand one and the fixed finger on the pincer is on the bottom. Crab claws have two pincers. The bottom one is a continuation of the main claw (is fixed) and the top one is hinged - and is called moveable.(the dactyl). Above: Concretion orientated with the top of the crab on the top side - I think ! I exposed just enough of the pincer to see what I think is the "fixed finger" the claw without a hinge on the bottom. This would therefore be the smaller left hand claw. Above: Closeup of the exposed claw. I think I can see the fixed finger on the bottom. Am I on the right track? I was getting just a little bit worried since there hasn't been any sign of the carapace yet. If I am on the right side it must be close! Thanks. Link to comment Share on other sites More sharing options...
CH4ShotCaller Posted January 20, 2014 Share Posted January 20, 2014 Looks good so far.. and you're right. Jason's Crab Concretion College is very handy. I've used his methods and advice for a few years now. Your photo looks like what you think is the top appears to be the bottom. I know that the 'fixed' dactyl is a solid/smooth taper without any interuption. I see signs of a hinge. let me dig through some pics and I'll add one as a guide for ya..... Anyone who has never made a mistake has never tried anything new. -Albert Einstein Link to comment Share on other sites More sharing options...
CH4ShotCaller Posted January 20, 2014 Share Posted January 20, 2014 Although this is not my image, it makes a great reference as a sort of guide. The fixed portion will be the ventral side of your specimen. 1 Anyone who has never made a mistake has never tried anything new. -Albert Einstein Link to comment Share on other sites More sharing options...
CH4ShotCaller Posted January 20, 2014 Share Posted January 20, 2014 BTW, this looks like the beginning of a nice piece and prep. Post pics of your progress and completion! I'd like to know what lies beneath! Anyone who has never made a mistake has never tried anything new. -Albert Einstein Link to comment Share on other sites More sharing options...
AeroMike Posted January 22, 2014 Share Posted January 22, 2014 I think I would like to prep one of these in the near future " This comment brought to you by the semi-famous AeroMike" Link to comment Share on other sites More sharing options...
Doctor Mud Posted January 23, 2014 Author Share Posted January 23, 2014 (edited) Thanks CH4ShotCaller, I've made some more progress and I'll post some pics soon. The rock is very hard and progress slow with the engraver I have, so I scored some lines using the engraver and chipped off some of the top of the concretion. I should say though that once you hit crab shell progress speeds up a lot on this guys since the rock is peeling away nicely from the shell I came across the other claw and this confirms the orientation. Since the big claw is always on the true right the claw that is exposed in the image above is the small claw and up is indeed up. Based on image at http://www.crystal-world.com/html/fossils/crustaceans/enlarged/crab_nz.htm The clear sections in the image are exposed now. I'll post and updated picture soon but you can see the small claw to the right in the previous picture that I have posted of the concretion. I was getting worried since I hadn't encountered the carapace. I had over estimated the hight of the carapace and it could be as low as the top of the small claw. I'm 1 cm above this depth now. Edited January 23, 2014 by Doctor Mud Link to comment Share on other sites More sharing options...
Doctor Mud Posted January 23, 2014 Author Share Posted January 23, 2014 Here's where I am at with this prep. That left claw is gonna be a biggun! Good to know which way is up now. Big claw on the left, small claw on the right. Link to comment Share on other sites More sharing options...
Doctor Mud Posted January 23, 2014 Author Share Posted January 23, 2014 Both images together for easier comparison. Bits I have exposed highlighted on a completed specimen (top image). My concretion (bottom image) Link to comment Share on other sites More sharing options...
CH4ShotCaller Posted January 23, 2014 Share Posted January 23, 2014 Lookin' Good! I need to contact my 'associates' for a dig soon..... found 3 sites that need attention. Keep posting! Anyone who has never made a mistake has never tried anything new. -Albert Einstein Link to comment Share on other sites More sharing options...
Doctor Mud Posted January 24, 2014 Author Share Posted January 24, 2014 Lookin' Good! I need to contact my 'associates' for a dig soon..... found 3 sites that need attention. Keep posting! Thanks for the positive encouragement! Good luck with the sites. Looking forward to hearing about your trips. Link to comment Share on other sites More sharing options...
CH4ShotCaller Posted January 28, 2014 Share Posted January 28, 2014 Just got internet access back again, a power surge knocked out my cable last week, getting back in here was limited at best . Looking forward to seeing your progress. Will take that field trip next week and post pics! Anyone who has never made a mistake has never tried anything new. -Albert Einstein Link to comment Share on other sites More sharing options...
Doctor Mud Posted January 29, 2014 Author Share Posted January 29, 2014 Just got internet access back again, a power surge knocked out my cable last week, getting back in here was limited at best . Looking forward to seeing your progress. Will take that field trip next week and post pics! Nice to hear from you again! Can't wait to hear about your adventures. Whats the weather like in your neck of the woods? I finally hit carapace the other day. On the plus side the carapace is an unusual yellow and orange colour. Interesting colour scheme - brown claws yellow-orange carapace (so-far). Was hoping that progress would speed up once I hit the carapace since the matrix was just falling off the claws. Unfortunately the carapace is slightly "sticky" and soft. No where near as bad as it could be, just means that progress is a little slower and I need to work under the scope. Not as bad as my previous crab - it was small and ultra sticky (matrix doesn't chip off in a nice way) and very soft in places. You had to peel away matrix in small chunks and stablise frequently with PVA, other-wise it would disintegrate (usually followed by some choice words....lucky for the loud engraver!) Crab concs are a mixed bag and thats why I collected several to make sure that I got myself a goodun after all this. I still look at this as a process (that I enjoy the challenge of) and not a race to the end product. I find that this approach (almost) keeps me sane I'll post pics soon. Link to comment Share on other sites More sharing options...
CH4ShotCaller Posted January 29, 2014 Share Posted January 29, 2014 Our weather here has been relatively dry this rainy season, but cold. The extended forecast looks favorable for a dig next week! You're right about the concretions being a mixed bag. I have several that are poorly preserved, partial and well preserved. Color range from pyrite, orange, copper, dark brown, black and chalky pink. I've got 3 that I'm working that are very difficult due to poor preservation or just too sticky. My next area to explore this Saturday will be a place where rumor has it that several ribs, vertebrae and some skulls have been found. Not sure if this site is Oligocene or part Miocene. It's part of a cut from the Columbia River. I'll be grinning ear to ear if I find part of a Desmostylus or Squalodon. Post pics when you get a chance! Anyone who has never made a mistake has never tried anything new. -Albert Einstein Link to comment Share on other sites More sharing options...
Doctor Mud Posted February 21, 2014 Author Share Posted February 21, 2014 (edited) Hey Shotcaller, Any luck on your trip? Hope you found some good stuff. Thought I would post a couple of progress shots of the crab I've been working on. Its been a learning experience working on a large almost complete crab. The rock is very hard, so through talking with others I have learnt that I shouldn't be afraid to - very carefully - use a chisel to remove larger areas of rock. Its been useful to collect as many images as possible of the crab biology and be prepared for surprises. Just when you think you know which way the crab shell is going, there will be a crack or some sort of postion change. Anyway - so far so good. It was a bit sticky on the top and I had to use a scope, but very nice colour and preservation. Once I got going down the sides and the legs the matrix is coming away more freely. These shots are from my phone - so sorry for the poorer image quality on these ones. The whole thing is about 25 cm across. Edited February 25, 2014 by Doctor Mud Link to comment Share on other sites More sharing options...
CH4ShotCaller Posted February 21, 2014 Share Posted February 21, 2014 The trip was good, did find some, mostly it was another recon mission. Hey! that concretion and prep is going very well! Very well indeed, keep up the good work! Anyone who has never made a mistake has never tried anything new. -Albert Einstein Link to comment Share on other sites More sharing options...
Doctor Mud Posted February 22, 2014 Author Share Posted February 22, 2014 Thanks shotcaller! I'm looking forward to getting to the claws. Saving them for last. Link to comment Share on other sites More sharing options...
RJB Posted February 24, 2014 Share Posted February 24, 2014 That crab is lookin good dr. mud. Lots of crabs are a bit sticky on top and then the rock comes off more easily once you start going down the sides. Also sounds to me that you have some real patience, and that my friend is going to make you a great preparator!!! Goooooooooooooo Drmud gooooooooooooo! RB Link to comment Share on other sites More sharing options...
Uncle Siphuncle Posted February 24, 2014 Share Posted February 24, 2014 Good thread. I cracked a bunch of Pulalius nodules open this weekend, obtained in trade from DLB. I guess I'll reference this thread while I begin attacking the lesser specimens first as time allows. 2 or 3 have great potential....now it's just a matter of workmanship (EEK!) Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
MB Posted February 24, 2014 Share Posted February 24, 2014 Wow, I'm impressed ! Good job http://www.mbfossilcrabs.com/ Link to comment Share on other sites More sharing options...
DLB Posted February 24, 2014 Share Posted February 24, 2014 Good thread. I cracked a bunch of Pulalius nodules open this weekend, obtained in trade from DLB. I guess I'll reference this thread while I begin attacking the lesser specimens first as time allows. 2 or 3 have great potential....now it's just a matter of workmanship (EEK!)I'm glad to see u are getting to those. I would love to see the pics of the finished ones. Link to comment Share on other sites More sharing options...
Uncle Siphuncle Posted February 25, 2014 Share Posted February 25, 2014 DLB-you may see them before completion to prevent novice mistakes. Grüße, Daniel A. Wöhr aus Südtexas "To the motivated go the spoils." Link to comment Share on other sites More sharing options...
Doctor Mud Posted February 25, 2014 Author Share Posted February 25, 2014 That crab is lookin good dr. mud. Lots of crabs are a bit sticky on top and then the rock comes off more easily once you start going down the sides. Also sounds to me that you have some real patience, and that my friend is going to make you a great preparator!!! Goooooooooooooo Drmud gooooooooooooo! RB Thanks RB! I was initially bummed when I found the top was sticky - but like you said things got easier. I can only aspire to your crab prepping greatness one day Link to comment Share on other sites More sharing options...
Doctor Mud Posted February 25, 2014 Author Share Posted February 25, 2014 Wow, I'm impressed ! Good job That means a lot coming from MB the "crabmeister" Link to comment Share on other sites More sharing options...
Doctor Mud Posted March 31, 2014 Author Share Posted March 31, 2014 Getting there! Slow going on the carapace. Yellow usually means danger with these crabs: soft and caution is needed. Interesting patterning on the top of the carapace. Haven't seen this before on a tumido. Link to comment Share on other sites More sharing options...
CH4ShotCaller Posted March 31, 2014 Share Posted March 31, 2014 Very nice! Your prep skills are good too! Anyone who has never made a mistake has never tried anything new. -Albert Einstein Link to comment Share on other sites More sharing options...
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