Coprolites in Geologic Time

   Coprolites have been found in strata as old as the Ordovician, but are more frequently found in Mesozoic and Cenozoic strata. The oldest known coprolites are from the Lower Paleozoic. Silurian coprolites have been found in the United States, Canada, Australia and Ireland. These coprolites date back to early vertebrate evolution, suggesting that their producers were either early fish or large invertebrates.

   In Mesozoic strata, coprolites are commonly found in marine shales, suggesting that aquatic settings are good for feces preservation. Some of the best spiral coprolites are found in Mesozoic strata. Many of the terrestrial coprolites found during this time could have been produced by a variety of different reptiles and other organisms. But By considering the shear abundance of dinosaurs and other sizable reptiles at this time, it is logical to assume that large coprolites were the products of these large creatures.

   However after the K-T extinction, when all dinosaurs had been wiped off the face of the earth, large fossilized feces were most likely produced by mammals and crocodiles.

NMC 40752 *

NMC 40750 *

NMC 51267

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