CENOZOIC ERA: AGE OF MAMMALS 



579 



Miocene 



The outline of North America was practically the same in the 

 Miocene (Fig. 530) as in the Eocene, with the exception of the 

 Mississippi embayment which was reduced in size, and the Florida 

 peninsula which was 



later in 



the 



formed 

 epoch. 



Atlantic and Gulf 

 Coasts. — On the 

 Atlantic and Gulf 

 coasts the strata rest 

 — often unconform- 

 ably — on the Eocene 

 or Oligocene, and, in 

 general, occur in a 

 narrow, interrupted 

 belt parallel to the 

 older formations 

 from Marthas Vine- 

 yard southward. The 

 Miocene strata in 

 some localities over- 

 lap the Eocene to 

 landward, com- 

 pletely concealing it. 

 The sediments on the 

 Atlantic coast con- 

 sist chiefly of sands, 

 clavs and marls ^ig. 53°- — Map showing the probable outline of 



• 1 • * 1 j North America during a portion of the Miocene. The 



With occasional beds cont i nen tal deposits are shown in solid black. (Modified 

 of diatomaceous after Schuchert.) 

 earth from 30 to 40 



feet thick. In Florida, Georgia, and in the Gulf region limestones 

 are the rule. The deposits of this epoch on the Atlantic and Gulf 

 coasts are comparatively thin, being only 700 feet thick in New 

 Jersey, 400 in Maryland, and even less in North Carolina. 



Economic Products of the Miocene. — The economic products of 

 the strata of this time are the phosphates of Florida, the oil of Louisi- 

 ana, and the diatomaceous earth of the Atlantic coast. 



