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Showing results for tags 'pennsylvanian sub-period'.
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I found this 16mm long, slightly tapered stick-like specimen at the Lost Creek Lake spillway near Jacksboro Texas in the Finis Shale member of the Graham formation, Late Pennsylvanian. Until I got a closer look I thought it was an encrusting Bryozoan but this texture appears to be much less organized than the pores on them. It is similar in texture, but more coarse, to the material found in the cores of some possible concretions which have been described as burrows with a core (?) that occur frequently there. The end view shows a thin, shell-like outer layer which is also on some of the cores of the concretions. A burrow with a core never made any sense to me anyway but I don't usually get a look at the core protruding out like these for a look at their surface texture so the similarity caught my eye. Besides the finer texture the ones in concretions do not seem to taper like this stick. I wonder if they could be some kind of plant material. We find some here but it is marine so it would be wood that floated out and sank. Here are two of the "burrows" or maybe concretions. The second one has odd, randomly spaced rings around it.
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- finis shale
- marine
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Here are three views of a 9 mm "Peritrochia sp." Girty 1909. It was found at the Lost Creek Lake spillway in Jacksboro. This proves that even a broken, partial fossil is worth taking home. In the first position you see the elaborate suture pattern characteristic of these Goniatites on the outermost whorl preserved. Notice the slight horizontal groove near the bottom edge. As it turns to reveal the next whorl below you can see the siphuncle as a vertical line and the outer edge of a septum, or chamber wall, at the bottom. Turning into the innermost whorl the septum comes into view at the top and the siphuncle is visible again. Here you also see another shallow groove crossing horizontally. These "constrictions" are found on some Pennsylvanian Goniatites. Peritrochia.mp4
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- cephalopod
- goniatite
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I'm trying to tell some of my brachiopods from Jacksboro Texas apart but the information I can find is confusing. I would like to see any examples of isolated pedicle valves of Marginifera lasallensis, Retaria lasallensis and Kutorginella lasallensis. They are about 2 cm wide, 1 cm deep and 1 cm tall, with a wide heart-shaped appearance and two delicate triangular ears that often break off. They also have 10-14 wrinkles near the nose with the smaller valve almost completely flat and the larger valve very curved, ending in a delicate scooping trail. They tend to occur in upper Misssourian and low to mid-Virgilian formations from Texas to Illinois. I would like pictures of the inside of the flat valve, lit from the side to enhance contrast if possible. Thanks for any help.
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- brachiopods
- pennsylvanian sub-period
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The Heard Museum in McKinney may not be the first place you think of for viewing fossils but they have a growing collection of locally found specimens including an Oligocece tortoise with an unusual view of the inside and a mosasaur left partly in the matrix to show how it was found. A couple of years ago they also started a program especially for amateur collectors. It's called "Collect it Yourself" and shows visitors what is possible for anyone with an interest in fossils to accomplish. Every six months a new collector brings enough material to fill the two display cases they set aside for this program and this time they are showing some of my collection from the famous Lost Creek dam site at Jacksboro Texas. The Finis Shale is a member of the Graham Formation in the Late Pennsylvanian Sub-period and is known for it's fossils with excellent perservation and an incredible level of diversity. I got lots of help with identification from Dr. Benjamin Neuman of Texas A&M University at Texarkana and other members of our Finis Shale Study Group hosted by Dr. Merlynd Nestell of U.T. Arlington. Lynne Hubner is the head of displays at the museum and did great job of arranging the 100+ fossils and making labels. All of them fit into one case except for one very large clam that filled another smaller case. The display will be there until some time in April. If you find yourself in the area this is a great place for a family stop. They also have hiking trails and many programs for all ages. here are the first two images of the display.
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- amateur collections
- finis shale
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