LIFE IN THE PAST l8l 



the character of our forests of to-day. Plants like 

 our willow and beech, poplar and sassafras appear in 

 great abundance. Their broad leaves serve better 

 than those of any earlier plants to catch the sunlight. 

 But in addition they offered such effective evaporat- 

 ing surface that they cast off rapidly the moisture 

 obtained from the ground by the plant. Accordingly 

 in the winter season, when the water in the ground 

 is frozen and not available for plant purposes, they 

 were forced to throw away their leaves. It is quite 

 possible that up to and including the time of the Car- 

 boniferous, plants were all evergreen. There had 

 been before this little variation in climate over the 

 globe. Life in the Cretaceous begins to take on dis- 

 tinctly its modern form. 



Among the reptiles of the forest there appear to 

 have been a few small creatures which to an observer 

 of those times, if there could have been an observer, 

 would have seemed of the utmost insignificance com- 

 pared with their giant cousins. 



These little creatures climbed up into the trees to 

 escape their enemies. There were some in whom 

 the skin, in front of the elbow and behind the wrist, 

 was loose, and stretched across the joint a little like 

 the wing of a bat. This reptile, climbing into the 

 trees to escape its enemies, found that this loose flap 

 of skin served it nicely, and sailed out of the trees 



