Afew Brachiopods From The Texas Permian

[jkfoam]

Years ago I had an opportunity to collect in the Glass Mountains near Marathon, Texas. This is a Permian exposure that is noted for its fossils that are silicified. I didn't find fossils weathered from the limestone matrix. What I did was to collect rocks that were roughly 6-8 inch cubes and brought them home. Then I dripped dilute hydrochloric acid (5%) and dissolved away the limestone freeing the silicified fossils. Unfortunately the silicification process was not 100% and most of the shells were paper thin and extremely fragile. Many times a shell would be destroyed by the effervescent action of the CO2 bubbles generated by the reaction of the HCl with the limestone. I did manage to save some. Also, 3 long distance career moves have also taken there toll on my collection as well. I hope I get another opportunity to go back and collect again.

Shown below are a few of the Brachiopods I collected. The first three pictures are of the most unusual brach I collected. It is a Prorichthofenian type brach. It is cone shaped rather like a coral. The cone is the pedicle valve and the brachial valve is located well within the margin of the cone. The opening of the cone is covered with a mesh.

[Harry Pristis]

Years ago I had an opportunity to collect in the Glass Mountains near Marathon, Texas. This is a Permian exposure that is noted for its fossils that are silicified. I didn't find fossils weathered from the limestone matrix. What I did was to collect rocks that were roughly 6-8 inch cubes and brought them home. Then I dripped dilute hydrochloric acid (5%) and dissolved away the limestone freeing the silicified fossils. Unfortunately the silicification process was not 100% and most of the shells were paper thin and extremely fragile. Many times a shell would be destroyed by the effervescent action of the CO2 bubbles generated by the reaction of the HCl with the limestone. I did manage to save some. Also, 3 long distance career moves have also taken there toll on my collection as well. I hope I get another opportunity to go back and collect again.

Shown below are a few of the Brachiopods I collected. The first three pictures are of the most unusual brach I collected. It is a Prorichthofenian type brach. It is cone shaped rather like a coral. The cone is the pedicle valve and the brachial valve is located well within the margin of the cone. The opening of the cone is covered with a mesh.

I admire your persistence, jkfoam. I did that, too. I guess if one were to do it regularly, one could build a collection of wonderful things. This was a challenge for me. This is what I kept in my drawer after all the time and effort.

------Harry Pristis

[Uncle Siphuncle]

I admire your persistence, jkfoam. I did that, too. I guess if one were to do it regularly, one could build a collection of wonderful things. This was a challenge for me. This is what I kept in my drawer after all the time and effort.

------Harry Pristis

Cool stuff guys. I've seen goniatites preserved in similar fashion from that site. I've never collected there before, but did find a bunch of Permian crinoid stems, a nice little goniatite, some corals, crinoid crown parts, and various gastropods such as Straparollus at a road cut 3-4 miles west of Marathon years ago in the Gaptank fm. I haven't collected much Permian material in TX as it is a pretty long haul from my neck of the woods.

[Roz]

Sure is a whole new world with small fossils. They have their own beauty. No wonder you like them.

[Gatorman]

Wow very nice stuff

[worthy 55]

Yes those are some cool little fossils. :cool:

[Harry Pristis]

I admire your persistence, jkfoam. I did that, too. I guess if one were to do it regularly, one could build a collection of wonderful things. This was a challenge for me. This is what I kept in my drawer after all the time and effort.

------Harry Pristis

I found another of those Glass Mountains fossils in the back of my drawer. I remember now the blocky, indurated limestone that is the Word Formation. The exposed limestone surfaces are weathered so that the silicified fossils (and there are lot of 'em) protrude from the surface. Handling blocks of this stuff is like handling bricks studded with razor blades. Leather gloves are shredded in minutes. It would be a serious matter to take a spill while clambering through the talus.

Great fun!

--------Harry Pristis

[geofossil]

Jkfoam and Harry,

Thanks for sharing your Glass Mountain material.

There was a great old fellow, the late Fred Labahn, who lived in Prescott Arizona. We were brachiopod keeners and I drooled over some of his specimens so he gave me up a 'chunk' of Matrix. I followed a different acid regimen from the above. Out of about a kilogram chunk I obtained about 60 or so brachs and some incredible bryozoa. They are exquisite in detail I used Fred's help and the Smithsonian muti volume series by Cooper and Grant to I.D. them. Fred even had a small trilobite and some gastropods etched out. I also never found a coral (Harry's great specimen above)

Echinaris. Most common Permian Productid

Neospirifer. Spirferid Shows interior view of 2 brachial valves

Grandispina kingorum. Exterior and interior view of pedicle valve. Productids

Yakovlevia. Productid. Exterior of pedicle valve

Yakovlevi. Productid. Interior of brachial valve

Tetragonetes and Leurosina (right) Productid. Interior of brachial valves

Prorichtofenia permiana. One valve has evolved into a cone...the other into a cap!

Collemataria (Lyttonia).Stropheminid. This family turned itself 'inside out' and has no resemblance to 'typical' brachiopods.

Allorhynchus. Rhychonellid. One of today's surviving orders.

Cleiothyridina and Composita. Athyrids. A dominant suborder until their demise at the great Permian extinction

Meekela. Strophomenid. Similar in 'appearance' to the order Rhynchonellid

[Gatorman]

Very interesting fossils I may yet become and invertebrate collector.

[Harry Pristis]

Jkfoam and Harry,

Thanks for sharing your Glass Mountain material.

There was a great old fellow, the late Fred Labahn, who lived in Prescott Arizona. We were brachiopod keeners and I drooled over some of his specimens so he gave me up a 'chunk' of Matrix. I followed a different acid regimen from the above. Out of about a kilogram chunk I obtained about 60 or so brachs and some incredible bryozoa. They are exquisite in detail I used Fred's help and the Smithsonian muti volume series by Cooper and Grant to I.D. them. Fred even had a small trilobite and some gastropods etched out. I also never found a coral (Harry's great specimen above)

Thanks for the pix. They are such exotic, wonderful fossils!

[jkfoam]

Geofossil,

Nice Brachs. It is amazing that you got that many whole brachs or brach valves from one 1Kg chunk of rock. I brought back probably 60 Kgs of material from the Glass Mountains and consumed around 120 gal of concentrated hydrochloric acid breaking down the rock and I don't think I have as much good material. I guess I need to go back and pick up some better rocks. LOL.

I use to have more but a box I was transporting them in was crushed in a move

Could you explain your acid regimen for the fossil recovery. I would appreciate the info as I hope to go back some day to get more material.

JKFoam

[geofossil]

Geofossil,

Nice Brachs. It is amazing that you got that many whole brachs or brach valves from one 1Kg chunk of rock. I brought back probably 60 Kgs of material from the Glass Mountains and consumed around 120 gal of concentrated hydrochloric acid breaking down the rock and I don't think I have as much good material. I guess I need to go back and pick up some better rocks. LOL.

I use to have more but a box I was transporting them in was crushed in a move

Could you explain your acid regimen for the fossil recovery. I would appreciate the info as I hope to go back some day to get more material.

JKFoam

I keep almost all of my non-displayed specimens of fossils in those 'Plano' brand plastic boxes (available at Walmart for sewing 'stuff', fishing, hobbies, etc.) the Glass Mountain material (and other fragile fossils) are in small cardboard boxes within the Plano container. I find this way I can open the hinged lid, see what's in the box and not unwrap things (and chance breakage).

I've written a few articles on acid treatment but in a nutshell when using some acids the key is to make up an 'acid soup'. Take the acid and dissolve some matrix in it and use it ....never use plain diluted acid. you can speed up making the soup by crushing the rock with a hammer into small bits. The % of acid is important but so is not having it act too fast on fresh material. Fossils like calcium phosphate teeth, silica brachs, etc. are much stonger (less brittle) when fortified in a 'soup'. Never replace all the old acid but perhaps a quarter at a time as you add diluted acid to it. If you have a lot of 'bubbling' then it's not soupy enough. Some bubbling is fine but not as much as with fresh diluted acid.

In preparing your block for an acid bath, coat the bottom (where it will sit) with a plastic spray or similar substance that won't dissolve in the particular acid. Then put your block on a plastic screen or whatever to suspend it in the acid. This way your specimens are less likely to crumble and collapse on themselves.

Super important to keep rinsing off your specimens after you get them out of the acid. Depending on the porosity of the material there can be acid residue that keeps eating away and your specimens will get brittle. Also, don't be too quick to toss out the 'crud' in the bottom....with luck under a microscope you can find some fascinating conodonts, ostracods,forams and other little fellows such as sand grain size brachs and gastropods.

Having said all this, best to experiment on small pieces. Sometimes when out collecting fossils i'll bring home some 'crappy stuff' just to play with in acid, use the saw on and so forth. Gives me an idea what to do without wrecking a good specimen (not that I've ever done that )

[jkfoam]

Geofossil,

Thanks for the information on your acid treatment technique. I most certainly will incorporate several of your techniques the next time I acid treat some fossils. You are certainly right about the requirement for a prolonged rinse of your material with water after the acid treatment to get rid of all the acid. If you don't the residual HCl vapors will corrode up all metal surfaces in your storage or display system.

JKFoam

[bamontgomery]

I'm working on sorting brachiopods from this formation right now.  I can't even begin to tell you how help this thread is.  Thank you so much!

Edited April 8, 2022 by bamontgomery

[Tidgy's Dad]

[bamontgomery]

This is my workstation as of this morning.  I'm going through three large slabs that were recovered decades ago and sitting in storage ever since.  The material sitting on top of the plates is remarkable--some of the best preserved material I've seen so far.  I've got specimens separated into sponges, crinoids, brochiopods/bivalves, bryozoans, trilobites, echinoids, and weird stuff that I can't identify yet.  I still have some of the detritus to go through, but am about to make the divisions more fined grained soon.  This is where I'm going to start.  Unfortunately, it's going to be a while before we give the limestone and silicified material an acid bath.

Edited April 8, 2022 by bamontgomery