Cretaceous Diatoms from Marca Shale collected in Panoche Hills, California

[bill2penn]

From Marca Shale Dosados Canyon nodule mixture "R-10", very close to Entogoniopsis polycistinorum but slightly different. Mounted in Zrax, stacked image taken with Leitz Pl Apo 40X/0.75. I will eventually retake the image using my Leitz Pl Apo 63X/1.40 but I hate using oil.

[bill2penn]

A damaged whole valve of an Odontotropis sp from the Marca shale Dosados Canyon nodule pieces "R-10". Stacked image using Leitz Pl Apo 40X/0.75.

[bill2penn]

Also from Dosados canyon nodule pieces "R-10" is this Aulacodiscus sp, possibly A. validus Barker and Meakin 1946? Stacked image taken with Leitz Pl Apo 40X/0.75 mounted in Zrax.
Greetings,
Bill

[Beatsy]

Nice finds Bill. The nodules certainly seem to have better-preserved specimens than the shales. In general.

Silica is essentially glass, albeit biogenic here. But look at the decay and degradation that happens to 2000-year-old Roman glass, or even a 50-year-old box of blank microscope slides, and you can't help but be amazed how pristine these forms remain after more than 66 *million* years underground 😲

Cheers
Beats

[Michael K.]

Hello Bill,

These are good pictures, but I often use oil, especially when I want to make small structures visible. Often there is a "sieve" in the large pores, which you can't see or can only see faintly with the 40mm or 60mm lens.

It's not that bad with the oil.

Regards
Michael

[bill2penn]

Here is a very rare (the only one I have found) but badly etched form found in the Dosados nodule pieces sample "R-9". Perhaps an Isthmia sp? Stacked image taken with Leitz Pl Apo 40X/0.75 mounted in Zrax. Width of entire image is 230 microns.

Greetings,
Bill

[Michael K.]

Hello Bill,

Very interesting shape that I haven't seen before. I've reworked the image on the PC. More details are coming out better. If I'm allowed, I'd be happy to post it, but I'd rather ask first.

Regards
Michael

[bill2penn]

Hello Michael,
I would be delighted if you edited and reposted my image to make it more informative. You are much, much better at this than I am. No need to ask me in the future!
Here's an Entogoniopsis polycistinorum or relative that was not as badly etched as previous ones.

Greetings!
Bill

[Michael K.]

Hello Bill,

here is the Picture.

[Päule Heck]

Heute habe ich drei bekannte Diatomeen von Bill's Präparaten fotografiert und in Fotoshop nachbearbeitet.
Viele Grüße
Päule


 

[bill2penn]

Merry Christmas and Happy New Years to all,

Here is an unknown form found in one of the Dosados Canyon nodules. Stacked image taken as dry strew with Leitz Pl Apo 40X/0.75. Any ideas?
Greetings,
Bill

[Michael K.]

Hello,
I suspect that this could be a fragment of a "Chaetoceros Seychellarum Karst." See Schmidt Atlas B3 / T327/ Fig. 12.
I was just guided by the shape, so I could be completely wrong.

Regards
Michael

[anne]

Dear Bill,
I have to check more papers, but my first thing to look in the book "Die Diatomeen der Fur Formation" page 276 and 277.
A kind of Pterotheca?
best anne

[bill2penn]

Greetings all,
Here is an interesting form I found in one of the nodules. Stacked image taken with Leitz Pl Apo 40X/0.75. Total image width is 100 microns. This reminds me of Triceratium bicornigerum but it has an extra vertex. It also has that little appendage in the center like T. bicornigerum does.

Best to all,
Bill

[bill2penn]

I think this is Euodiella tristictia. Thanks to Jonathan Crowther for the determination.