^^^^^^^ ^ i Diplacodon Beds 



Equ 



Tnpir, PccL'iry, BiBon, llama. 

 Megatherium, Mylodon. 



Equufl Beds. 



Eqiiut, TapirM. Elepliag 



PhohippUK Beds. 

 Pivjinppua, Mastodon, Bos, t 



Jliohippiis Beds. 



Mlolnppui, I'lcerat/ieilutn, Tliitio. 



Oi-eodoii Beds. 



Kdenlatea, lli/a^todon, Uyraeodon. 



BronLotheriuin Beds. 



Meno/iippiia, J)fenodiiH, Etntherium 



Epxhippug, Aiiijiiiodon. 

 Dinoceias Beds. 



Tinocerae, Uniti-II.emm. Li 



Orolappue, liclaieiei, Culono 

 Coryphodon Beds. 



Eolappua, Monkcjs, Carol vi 

 Herpenta 



e8. TilloaontR. Rodent 



Lif^nite Seviee. 



Ilydrueaurue, Dryptoaaurus. 



Pteranodoii Bed.'^, 



BirdB with Teelli, Uc&pei 

 FtetodactjlB, Plceiosaur 



Dakotd Group. 



Atlantosauiust Beds, 

 Diooaaura, Apatoaaurua, AUoaaurua, A'n: 

 plo^aurus 



Connecticut River Beds. 



Fiiat MammalB (Maraupiala), {Droinalhcnum). 

 Dinosaur Foot-printa, Ampliwaurna. 

 Crocodilea i^Belodon). 



Coal Jleasurea. 

 First Reptiles (?)■ 



Sub-cavboiiiferouB. 

 First known Ampbibiane (I^bjrintbodontB). 



Corniferous. 



a Upper Silurian. 



X Lower Siluiian. 



Primordial. 



No Veitebraies knowo. 



Fig. 302.-Section of the earth's crust, to illustrate vertebrate life in America. 

 (After Marsh.) (From Le Conte's Geology, American Book Co., Publishers.) 



393 



