Paleontology and geology
Cretaceous rocks are exposed in a north-south band across western Tennessee. These rocks are part of the Mississippi Embayment, an area covered by a shallow sea that flooded the region as North and South America moved farther apart during the breakup of the supercontinent of Pangea. Invertebrate fossils are abundant in these rocks, including clams, oysters, snails, and crinoids. The official state fossil of Tennessee is a small bivalve, Pterotrigonia thoracica, found in Cretaceous rocks. The only dinosaur bones found thus far in Tennessee are those of the plant-eating hadrosaur Edmontosaurus that lived during this time.