1905.] 



AMPHIBIANS AND REPTILES. 



235 



and Guatemala, also the Mexican Sierra Madre del Siii-. These 

 parts were in time annexed by Sonoraland. 



By the late Eocene, conditions wei-e so far consolidated that 

 there existed the present North American Continent, eastern and 



Text-fis-. 31. 



LAND DUHIN& 

 £AHLY CREIACEOUS EPOCH 



n 



DURING LVTER CRETACEOTTS, ' 

 OR EARLY EOCENE 



in 



DURING EATER E.OCENII 



Diagrams to illustrate tlie contours of Mexico at different geological ages. 



western halves joined, and the latter extending southwards as the 

 present Mexico and part of Central America. Brazilia had grown 

 into South America, but the two continents were still separated, 

 the Atlantic and Pacific communicating across the pi'esent 

 Isthmus of Panama and pi'obably further north. 



