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Mike Owens

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Lance's specimen, in the Gallery, prompted me to post these photos. He has a very nice large specimen in near perfect condition. Mine is near as large, but more in the condition you will find them in. Large ones tend to get broken easier, as is mine, than the smaller ones. With both specimens exbiting the same characteristics, a water stain like mark on the face of both, I would hazzard to guess they both came out of Johnson County, Texas. There is a roadcut, Hwy 67, just Southwest of Cleburne about 2 miles past the Nolan River, that produces these nice Echonoids. There are also some gulleys on the other side of the fence, make that private property, :rolleyes: that also produces them & nice Ammonites. I haven't been there since '85, so I don't know if it's "mined out" or not. Maybe Lance has been there more recently & could comment. This is the only area I know of that specimens, of this size, can be found.

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-----"Your Texas Connection!"------

Fossils: Windows to the past

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I like Macrasters too! I have found them in the Boracho fm of West TX (M. kentensis) and also from south of Austin all the way up into Oklahoma past Lake Texoma, but most of them seem to be between Fort Worth and Lake Texoma. As for specimens in the tan to brown spectrum, most in my collection tend to come from the Weno fm which outcrops from Lake Texoma down through Fort Worth where it thins and narrows in outcrop heading south toward Temple (like the other Washita formations) where these formations are mapped undivided as the Georgetown fm which is intermittently exposed though Austin, San Antonio, and out past Del Rio.

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Grüße,

Daniel A. Wöhr aus Südtexas

"To the motivated go the spoils."

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I like Macrasters too! I have found them in the Boracho fm of West TX (M. kentensis) and also from south of Austin all the way up into Oklahoma past Lake Texoma, but most of them seem to be between Fort Worth and Lake Texoma. As for specimens in the tan to brown spectrum, most in my collection tend to come from the Weno fm which outcrops from Lake Texoma down through Fort Worth where it thins and narrows in outcrop heading south toward Temple (like the other Washita formations) where these formations are mapped undivided as the Georgetown fm which is intermittently exposed though Austin, San Antonio, and out past Del Rio.

Dan,

Great photos! B) beautiful specimens! :) It's nice to know there are way more sites producing these large Echinoids. Thank you for your input. One never gets too old to learn. :shades:

Thanks,

Mike

-----"Your Texas Connection!"------

Fossils: Windows to the past

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Mike

That 25 specimen Macraster denisonensis(?) cluster also has a Goniophorus scotti in the mix. For greatest numbers of big Macrasters (2-5 inches) concentrate on the Duck Creek and Fort Worth formations from Fort Worth to the shorelines of Lake Texoma using the Atlas of Texas Dallas and Sherman quadrangles to trace outcrop. I find good ones in creeks but visiting recent excavation in the outcrop area after a couple hard rains is a sure fire recipe for success. Generally what I've seen is that the upper 6+/- feet of the Kdc or Kfw at a given exposure tend to be leached to a tan color with echinoids therein being solution etched and of mediocre to poor quality, but this doesn't seem to adversely effect the ammonites. Perhaps the tan color is due to broken down pyrite, but I'm just speculating. Deeper excavations tend to reveal the unleached gray layers which often have echinoids preserved in superb detail with attached pyrite crystals as shown in my images. As a general rule when you are finding Mortoniceras ammonites you are in a good area for Macraster and Holaster echinoids (Kdc, Kfw, Kwe). The ammonites tend to be in the harder limestone layers while the echinoids are mostly in the softer marly layers. Hope this helps.

Grüße,

Daniel A. Wöhr aus Südtexas

"To the motivated go the spoils."

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