BOTANICAL CHARACTER. 41 



in such an environment if they were reintroduced, at least the 

 only adverse factor would be the pressure of a more complex 

 flora. This, incidentally, seems to have been the ancient factor 

 which largely explains their present distribution. 



With regard to the climate of the Raritan, the data for forming 

 any adequate opinion are altogether insufficient. Although JVid- 

 dringtonitcs and Frenelopsis suggest a certain amount of aridity, 

 this is overwhelmingly opposed by the ferns and cycads and a 

 host of other forms. The climate was certainly more uniform 

 than at present, both as regards seasonal changes and zonal dif- 

 ferentiation. 



When large numbers of identical species range from Green- 

 land through southern New England, New Jersey, Maryland, 

 and the Carolinas to Alabama, and when we find identical Dakota 

 Group forms in Minnesota and Kansas and then in Texas, and 

 then in the Upper Cretaceous of Patagonia, it would seem that 

 the proof that CretJ.ceous climate was very different, as a whole, 

 from modern climate rested on a very secure foundation. 



