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May be a bit of an odd question, but I was wondering what horizons or layers are the most fossiliferous in the Conasauga Formation. I've heard about the Tibbs Bridge site (RIP), but that site exposed a calcareous, light-colored shale from the upper part of the Conasauga. From what I read online it seems that most of the trilobite beds are located in the upper shale layers of the formation, but I was wondering if anyone else knew if the other parts of the formation had anything? 

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Thomas.Dodson

There are other parts with well known fossils. Tibbs Bridge was an example in the Upper, or Mid to Outer Shelf Lagerstatte Unit of the Conasauga (Bolaspidella assemblage zone). The Lower, or Inner Shelf Lagerstatte Unit (Ehmaniella or, for older sources, Oryctocephalus assemblage zone) is also highly fossiliferous. Some Figures from Schwimmer's Publications on the subject of Conasauga stratigraphy and paleontology you might find useful.

Untitled3.png.6d3c5455cbd3e9b9900ccdeb5f65a5b6.png

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Untitled.png.759369af751785973081f091e3b94350.png

 

Relevant Publications discussing the other zones of the Conasauga:

 

Taxonomy and Biostratigraphic Significance of Some Middle Cambrian Trilobites from the Conasauga Formation in Western Georgia
Author(s): David R. Schwimmer

Source: Journal of Paleontology, Vol. 63, No. 4 (Jul., 1989), pp. 484-494

 

Exceptional Fossil Preservation in the Conasauga Formation, Cambrian, Northwestern

Georgia, USA
Author(s): David R. Schwimmer and William M. Montante Source: PALAIOS, Vol. 22, No. 4 (Jul., 2007), pp. 360-372 Published by: SEPM Society for Sedimentary Geology

Stable URL: https://www.jstor.org/stable/27670429

 

Glyptagnostus and Associated Trilobites in the United States By Allison Palmer, 1962 also references Conasauga Formation sites from other states but has less of a focus on the stratigraphy and the exact position of the Conasauga beds.

 

 

 

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23 minutes ago, Thomas.Dodson said:

There are other parts with well known fossils. Tibbs Bridge was an example in the Upper, or Mid to Outer Shelf Lagerstatte Unit of the Conasauga (Bolaspidella assemblage zone). The Lower, or Inner Shelf Lagerstatte Unit (Ehmaniella or, for older sources, Oryctocephalus assemblage zone) is also highly fossiliferous. Some Figures from Schwimmer's Publications on the subject of Conasauga stratigraphy and paleontology you might find useful.

Untitled3.png.6d3c5455cbd3e9b9900ccdeb5f65a5b6.png

Untitled2.png.8a4d37597e73b5e041b881b040250149.png

Untitled.png.759369af751785973081f091e3b94350.png

 

Relevant Publications discussing the other zones of the Conasauga:

 

Taxonomy and Biostratigraphic Significance of Some Middle Cambrian Trilobites from the Conasauga Formation in Western Georgia
Author(s): David R. Schwimmer

Source: Journal of Paleontology, Vol. 63, No. 4 (Jul., 1989), pp. 484-494

 

Exceptional Fossil Preservation in the Conasauga Formation, Cambrian, Northwestern

Georgia, USA
Author(s): David R. Schwimmer and William M. Montante Source: PALAIOS, Vol. 22, No. 4 (Jul., 2007), pp. 360-372 Published by: SEPM Society for Sedimentary Geology

Stable URL: https://www.jstor.org/stable/27670429

 

Glyptagnostus and Associated Trilobites in the United States By Allison Palmer, 1962 also references Conasauga Formation sites from other states but has less of a focus on the stratigraphy and the exact position of the Conasauga beds.

 

 

 

 

Interesting, that helps a lot. I guess the only question I have from that is if you happen to know if the trilobite zones are also present in the limestone units? I know they're located in different geographic areas, but I was wondering if the Maysville has the same kind of fauna, given it's roughly stratigraphically equivalent to the upper Conasauga in Georgia. 

 

 

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Thomas.Dodson
44 minutes ago, EMP said:

 

Interesting, that helps a lot. I guess the only question I have from that is if you happen to know if the trilobite zones are also present in the limestone units? I know they're located in different geographic areas, but I was wondering if the Maysville has the same kind of fauna, given it's roughly stratigraphically equivalent to the upper Conasauga in Georgia. 

 

 

Do you mean the Maynardville or the Maryville? I found this stratigraphic correlation chart for the Cambrian of East Tennessee that gives a clearer distinction of how they line up with the Trilobite Zones there. They're assigned to the specific zones by the presence of indicator species although I don't know how many other species overlap. I do know the Tibbs Bridge site matches well with Cedar Bluff Alabama sites aside from the absence of Aphelaspis brachyphasis in Cedar Bluff. Schwimmer speculates on the reason for this in the paper describing them from Georgia. 

 

Untitled.png.b1a40c12ba3cb4c6eae78d3cffd703b6.png

Kozar, M.G., Weber, J.L., and Walker, K.R., 1990, Field and Modeling studies of Cambrian carbonate cycles, Virginia Appalachians-Discussion: Journal of Sedimentary Petrology, v. 60, p. 790-794.

 

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piranha

Maysville is Ordovician. This paper has a list of Maryville fauna.

 

Resser, C.E. 1942. Faunal Content of the Maryville Formation.

Smithsonian Miscellaneous Collections, 101(10):1-8  PDF LINK

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