Pliocene
chesapecten jeffersonius
Virginia has no official rock or gemstone. You might consider listing the official fossil which is Chesapecten jeffersonius which was given official status in 1993 by the legislature.
Virginia doesn't have a state dinosaur, and its state fossil is a scallop called Chesapecten jeffersonius. However, birds are dinosaurs, so if you count the state bird, the state dinosaur is the cardinal.
The extinction of the dinosaurs did not occur during the Cenozoic era. Dinosaurs went extinct at the end of the Mesozoic era, which preceded the Cenozoic era.
Antebellum Era
Simple. There is no state rock of Virginia. A state fossil, yes (the fossil scallop, Chesapecten). A state rock, alas, no.
1850 - 1920
The colonization of land by plants did not occur during the Cenozoic era as it happened earlier during the Paleozoic era.
During the Cenozoic era, which began around 66 million years ago, dinosaurs went extinct at the end of the previous Mesozoic era. Therefore, the existence of dinosaurs is something that did not occur during the Cenozoic era.
Colonial
200 b.C.
no but it might happen in the futurre