Forum Replies Created
April 25, 2020 at 7:45 pm #68211
@theodore-gray Frankly, they all look alike to me. However, I suggest you obtain a copy of Collector’s Guide to Texas Cretaceous Echinoids by William W Morgan, Schiffer publishing, 2016. He’s got all of them covered.February 6, 2020 at 3:09 pm #64644
The normal tool we use is Chicago Pneumatic scribe which comes in any number of sizes depending on what you want to use it for. Paleo Tools has a wide selection of the Chicago and also services them. We have a coarse one for removing bulk matrix and a finer tipped one for finer work. Invertebrate paleo has some new tools that they call “German” which are Universal Tool air scribes UT8617. I was told they were around $900 apiece but online I see them listed for around $255. The Chicago runs around the same.
I hope this helps
JackFebruary 5, 2020 at 2:24 pm #64624
@samantha-ocon I could check to see what they use in the Cincinnati Museum prep labs. Maybe that will help. I am laid up with a foot injury so I’ll have to get one of my friends to check.
JackFebruary 5, 2020 at 1:12 pm #64623
@samantha-ocon I am sorry I can’t offer any help along those lines. I don’t use this type of equipment as it isn’t generally needed for most fossils around here. “hard core” people who do lots of this type of work are the ones who use these. If you do get one of these remember that you still need a strong suction device pulling away the material so you don’t breath the fines. These fines can cause lung damage even many years in the future.
JackSeptember 16, 2019 at 4:11 pm #60286
@sadie-mills @carl-lewis A lot depends on the preservation material for the trilobite. Most will be calcitic and will be adversely affected by any chemical cleaner that will dissolve limestone. To remove loose or soft shale or mud a toothbrush with water and an optional mild detergent will help. If the limestone matrix is covering part of the trilobite there is no free lunch . . . air scribes and air abrasive cleaning by an expert preparator are required. Inexperienced use of these tools can ruin a fossil in the blink of an eye.July 26, 2019 at 4:25 pm #57939July 26, 2019 at 4:21 pm #57932
@bheimbrock Hey Bill! Don’t be trying to replace me as Dry Dredgers bulletin editor. I like doing that 🙂July 26, 2019 at 2:27 pm #57909June 19, 2019 at 4:32 pm #56140
I can only address cleaning as I don’t use a microscope for photography (macro lenses only).
A stereoscope with step-wise or variable power is the best for cleaning small specimens. Larger specimens can be worked on using a ring light with a magnifying lens in the center. The key is you want both of your hands free to manipulate and work on the specimen. The most versatile stereoscope would be one mounted on a boom stand. This type of mount allows the most range of motion both vertically and horizontally. A stand with the microscope mounted on a post is next best as that allows a bigger vertical range of motion than a fixed base type scope.
I find I do most of my cleaning with 10x magnification. Sometimes I use 15x or 20x but not very often.
When doing cleaning where water is involved, some microscopes allow an additional glass splatter guard that can be mounted below the objective lens.
Stereoscopes can be very expensive when purchased new especially if they are big name brands like Nikon, Canon, Leica, Bausch & Lomb. Good used ones can be had for less money but be sure to check it out first as repairs are expensive. Reasonably priced new stereoscopes of lesser known brands can be had for $300. Always make sure the optics are good and there is no distortion (view a straight line grid to be sure all lines remain parallel).January 27, 2019 at 10:13 pm #45777
@rleder Hi Ronny. I was going back through old forums and thought I’d update my previous answer about the Cincinnati Museum Center status. The museum is open finally! It’s been open for a month or so now. However, they are only able to install exhibits in stages so only a few new exhibits are open (and none of the old ones). They are revamping everything and only a few things will be as they were before the shut-down (the physical cave and ice age walk through are the same but will end up with new peripherals). The only thing open in the natural history side is a brand new dinosaur exhibit with seven skeletons. It’s pretty cool. The prep lab is open so visitors can see people working on fossils through a viewing window. They just opened the OMNI Max theater. It has gone from film to digital with new screens, new audio and wider seats to fit our population 😉 The mosaics that fill the dome in the rotunda have all been cleaned one tile at a time. This is amazing.
I hope your new museum is coming along as well.December 29, 2018 at 8:15 pm #44596
@karen-metcalf This looks like a mastodon tooth to me. Even if it is some other kind of tooth it is a super find!
JackSeptember 12, 2018 at 11:08 pm #41504
@greg-kessinger Canadian pebble is probable. The material on the surface would not have survived the glacial action that rounded the pebble. My thought is that this is a post glacial mineralogic creation, perhaps caliche?
From my own experience, I have a small pebble that I found as a kid that was split in two with both sides together. It is red sandstone (?) and inside is the impression of a Devonian brachiopod. So this one made it from Canada to Dayton, Ohio.
The other improbable specimen was found by a fellow Dry Dredger here in Cincinnati. This was a small slab with a complete well preserved Devonian Phacops trilobite from the Toledo, Ohio area. How that survived is unimaginable.
JackJuly 10, 2018 at 8:47 pm #39857June 25, 2018 at 10:17 pm #39459
@david-powers Your mesh objects are bryozoan fronds. Possibly from the genus Archimedes. I’m not familiar with this particular formation but in the Mississippian of Indiana they would be from Archimedes most likely.
JackMay 3, 2018 at 5:17 pm #35777March 19, 2018 at 7:56 pm #31539
@geoff-ruonavarra I don’t see any fossils myself. It looks like a piece of man made terrazzo or something that was cut with a diamond saw. A natural break would not be that smooth and parallel sided, especially since the smooth break goes through all the clasts with no unevenness. That’s my opinion.February 24, 2018 at 6:18 pm #30785
@hunter-thurmond Poop! It looks like a fecal string to me. I found crap like that (pun intended) in my screenings at Venice Beach years ago.
JackJanuary 31, 2018 at 10:27 pm #30580
@inkar-arzah At first glance, this looks like a fragment of a worn horn coral (Grewingkia) to me.December 6, 2017 at 10:16 pm #29537
@gail-tennant, @jim-chandler I’d say it is definitely bone and I don’t see any matrix on it. You need to have someone put eyes on the specimen before you start removing anything that you think is matrix as it may be part of the fossil.
The specimen looks quite porous. Is it fairly light in weight or really heavy like a rock of the same size? I agree with Jim in that it could be a hoof core.
JackNovember 25, 2017 at 10:25 pm #29371
@jordan-oldham Jordan, I don’t see in your description where you found this other than near your university. You didn’t identify the university. Sorry if I missed something. I’d like to see clearer photos in hi-res that I could enlarge. Having said that, here is what I think so far:
This does appear to be a Eucalyptocrinites (this is the currently accepted genus as they have dropped using “crinus” on this one).
The crinoids in Fossils of Ohio from the Cedarville Dolomite are internal molds. No actual original calyx plates are preserved. That’s why they may look like blobs plus the illustrations of them in Fossils of Ohio is not all that great. Is this the correct Formation where this was found? From what I can see, your specimen appears to have original calyx plates and that would be very unusual for the dolomite. The Eucalyptocrinites proboscidialis from the Cedarville Dolomite illustrated in Fossils of Ohio is the same illustration used in the Treatise (T497, Fig 299, 1d). The specimen is an internal mold and does not appear to be what you have.