458 



MESOZOIC ERA— AGE OF REPTILES. 



Fig. 726. 



Fig. 727. 



Fig. 728. 



Fig. 729. 



Figs. 726-729.— Fossils of North Carolina and Kichmond Coal-Basins (after Emmons): 726. 

 Neuropteris limefolia— Richmond Coal. 727. Pecopteris falcatus. 728. Neuropteris. 729. Jaw 

 of Dromatherium sylvestre. 



these two basins. Tridactyl tracks like those in Connecticut have also 

 been found in New Jersey and in Pennsylvania. 



Other Patches. — In other patches, especially in New Jersey, Penn- 

 sylvania, and Nova Scotia, reptilian bones and teeth have been found, 

 representing Dinosaurs and Orocodilians or Lacertians. 



Interior Plains and Pacific Slope. — The Jura-Trias of the interior 

 plains are singularly deficient in fossils. The gypsum in many of them 

 furnishes the explanation. They were probably formed in interior and 



Fig. 730. 



Fig. 731. 



Figs. 730, 



731.— Jurassic Fossils of Utah (after Meek): 730. Belemnites densus. 731. Gryphaea 

 calceola. 



very salt seas, which are usually deficient in life. The two periods are, 

 however, in some places at least, better separated than on the Atlantic 

 slope, probably because of more variable conditions. 



