176 SKETCHES OF CREATION. 



sublime philosophy of paleontological studios, and assures 

 us that one enduring and infinite Intelligence has planned 

 and executed every part of creation. 



Crowds of reptile forms have passed before our view, but 

 we have only just arrived at the culmination of the reign 

 of reptiles — the Herpetarchy of the world's history. The 

 Jurassic Age followed the Triassic. Before this time the 

 Trilobites of the Paleozoic Ages were known only in his- 

 tory. The plain-chambered shells had been followed by 

 lobulate-chambered shells — the Goniatites — and these were 

 now, to a great extent, superseded by the Ammonites, a 

 family of chambered shells with dorsal siphons and ex- 

 tremely complicated partitions betAveen the chambers. So 

 the complexity of Nature's products increased with her 

 age. Most of the Ammonites were closely coiled. In their 

 modifications and decorations the exuberance of Nature 

 effloresced in hundreds of distinct species. Six hundred 

 representatives of this peculiarly European family are ex- 

 hibited in the museum of the University of Michigan— one 

 of the results of the tireless industry of Dr. C. Rominger. 

 The land was clothed with a vegetation quite similar to 

 that of the present day ; but the climate was yet warmer 

 than at present, and many types of plants and animals, 

 which to-day are confined within the tropics, were then en- 

 abled to range to the Arctic circle (Fig. 70). 



The great feature of the age was its reptiles. These 

 were represented in all their orders except serpents. Ba- 

 trachians also existed, if we may judge from some remains 

 found in North Carolina and Pennsylvania in sandstones 

 accumulated probably during this age. These remains be- 

 long to the genus Composaitru-s, and reveal, like the Car- 

 boniferous Batrachians, some relationship with the Laby- 

 rinthodonts. Better characterized Labyrinthodonts have 

 been described under the name of Centemodon, from the 



