Life Progressive. 



415 



wonderful dicotyledonous flora of the Upper Cretaceous 

 similarly surprise us without any prophetic annunciation 

 from the older Jurassic. Many other instances might be 

 cited, but enough has been said to show that the problem 

 is one environed with profound difficulties. 



As we pass from the older rocks into the newer, we not 

 only find that the animals of each successive formation 

 become gradually more and more like existing species upon 

 the globe, but we also find that there has been a gradual 



MESOZOIC FLORA AND FAUNA. 

 Cycads, Pandanus, Deinosaurs, Birds and Pterodactyl. 



progression and development in the types of animal life 

 which characterize the geological ages. Taking the earliest- 

 known and oldest examples of any given group, it can some- 

 times be shown that these primitive forms, even though they 

 are highly organized themselves, possessed certain charac- 

 ters such as are now only to be met with in the young of 

 their existing representatives. Such characters, which are 

 technically called embryonic characters, do not prevent the 

 frequent attainment by their possessors of sizes much more 



