Trilobites of the Wheeler Shale Formation
Trilobites of the Wheeler Shale Formation include Elrathia kingi and Peronopsis interstrictus. While there are many species of trilobites that come from the rocks of the Wheeler Shale Formation these are the two most common.
Elrathia kingi belong to the order of trilobites called Ptychopariida. The Peronopsis belong to the order Agnostida. The Wheeler Shale Formation is one of the most famous middle Cambrian trilobite locations is the world. The trilobites we sell are about 510 million years old and are found in the House Range, Millard County, Utah.
The Elrathia Kingii trilobites were benthic feeders, meaning that they lived and dined on the ocean floor in deeper water. This is the most common trilobite fossil found in North America. It is beleived that they lived in very low oxygen environments which would explain why they fossilized in such abundance. Elrathia trilos are found with and without cheeks. The cheeks are the rounded sides of the cephalon or head. This is where the exoskelleton split when molting so a trilobite without cheeks represents a molted exoskeleton rather than the fossil of a complete trilobite.
The peronopsis trilobites are the worlds smallest trilobite ranging in size from 1 to 10 mm, or less than 1/2 inch! These little guys were likley bottom feeding scavengers. The Agnostida order of trilobites get their name from the fact that its hard to tell if they are comming or going. The heads and tails of this type of trilobite look almost the same. Peronopsis trilobites, unlike most other trilobites did not have eyes.
The Elrathia Kingii trilobites were benthic feeders, meaning that they lived and dined on the ocean floor in deeper water. This is the most common trilobite fossil found in North America. It is beleived that they lived in very low oxygen environments which would explain why they fossilized in such abundance. Elrathia trilos are found with and without cheeks. The cheeks are the rounded sides of the cephalon or head. This is where the exoskelleton split when molting so a trilobite without cheeks represents a molted exoskeleton rather than the fossil of a complete trilobite.
The peronopsis trilobites are the worlds smallest trilobite ranging in size from 1 to 10 mm, or less than 1/2 inch! These little guys were likley bottom feeding scavengers. The Agnostida order of trilobites get their name from the fact that its hard to tell if they are comming or going. The heads and tails of this type of trilobite look almost the same. Peronopsis trilobites, unlike most other trilobites did not have eyes.
Common Trilobites of The Wheeler Shale
Elrathia Kingii Trilobite With Cheeks
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Elrathia Kingii Trilobite No Cheeks
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Peronopsis Trilobite
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The Trilobites of The Wheeler Shale Timeline
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Paleozoic Era
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Cambrian Period
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Ordovician Period
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Silurian Period
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Devonian Period
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Carboniferous Period
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Permian Period
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| . | Wheeler Shale Trilobites |
The Wheeler Shale Formation is a group of rock layers made up of highly calcareous shale, shaley limestone, mudstone and thin, flaggy limestone. This formation, famous for its fossils. is found in the House Range of Millard County, Utah. During the Cambrian Period This part of North America was near the equator and twisted about 90 degrees from its present orientation as part of the Continent Laurentia.
