GEOLOGICAL SURVEY OF THE TEKEITOEIES. 427 



Eocene sandstone, though the characters of marine vegetables ai^pear 

 to have been preserved somewhat longer in the series of geological divis- 

 ions. Such a total discordance of types cannot be supposed for a flora 

 of a same period, not even for members separated by a great thickness 

 of strata. Most of the genera of animal fossils, and a large number of 

 species, too, are represented in all the Cretaceous divisions, from the 

 lowest member to the base of the Eocene. In the Tertiary formations 

 the vegetable types represented by most of the genera, and by a large 

 number of species, too, are recognized identical in the whole extent of 

 the measures. The same remark can be applied to the vegetable and 

 animal remains of all the formations. It is, then, judicious to admit as 

 a conclusion, that such a marked disconnection of the typical character 

 of a whole flora is a positive evidence of a new geological period, and 

 that, therefore, the whole Lignitic of the Eocky Mountains is, from the 

 base of the fucoidal sandstone, a Tertiary-Eocene formation. 



