THE HISTORY OF LIFE 



importance. Here we come to the end of the Paleozoic, 

 or period of the old life, as we choose to call it. In 



From Proceedings U. S. National Museum 



FIG. 26. Wing of fossil cockroach (Phoberoblatta reticulata) from the Carboniferous 

 (Pennsylvanian) rocks near Brookville, Pennsylvania. Magnified about two 

 diameters. 



reality it was the young life, the youth of the world, and 

 we are the real veterans. 



8. The Mesozoic (middle life) period is called the age The age of 

 of reptiles. It may have lasted about nine million years, 

 certainly not more than half the length of the Paleozoic. 

 It begins with the Triassic and ends with the Creta- 

 ceous, the latter name from creta, chalk, because it is 

 the period of the chalk cliffs of Albion. Early in the 



reptiles 



