330 UNITED STATES GEOLOGICAL SURVEY— TERTIARY FLORA, 



The whole number of species in this table is three hundred and twenty- 

 nine, two hundred of which are credited to the Lower Lignitic. 



This superiority of the representatives of the flora of the lower group is 

 due, first to tlie wide extent in surface and to the thickness of this division 

 and of its seams of lignite, which are already widely worked, thus expos- 

 ing at many localities beds of shale abounding in vegetable remains; then 

 to more careful researches pursued in this division of the Tertiary than 

 in any other. These careful researches have brought on the discovery of 

 fruits and seeds at Grolden and Black Buttes. Of these two hundred species, 

 fifty-seven are credited to Golden only, thirty-one to Black Buttes, and 

 seventeen to Point of Rocks. 



Considering first the relation between the Bitter Creek series or the 

 Lower Ligaitic of Wyoming with that of Colorado, we find Black Buttes 

 and Golden with nineteen species in common, four of which have been 

 found also at the Raton Mountains, and four at other localities of the Lower 

 Lignitic of Colorado, and besides, out of the species of Point of Rocks, 

 Golden has eight, three of them seen also at other named localities of 

 tlie Colorado Basin, or in all we count twenty-six species found in both the 

 Colorado and the Wyoming Lower Lignitic. These and the peculiar types 

 represented by the species are sufficient t(j indicate the synchronism of the 

 formations. 



The different localities referred to the Lower Lignitic group in the 

 Colorado Basin have their relation recorded by ten of the Raton Mountains, 

 seven of which are at Golden only, and three more at Golden and Marshall's. 

 Besides these. Golden has three of its species at Marshall's, four at Sand 

 Creek, one identified with Canon City, which has one of its species also at 

 Sand Creek. Erie has one species of the Raton Mountains. As seen from 

 the table, Sand Creek, and especially Marshall's, Cafion City, and Erie, 

 are as yet represented by very few species, and, therefore, the relation 

 between the localities is comparatively and proportionally quite as evident 

 as it is between Black Buttes and Golden 



The number of the species of the lower group represented in the upper 

 divisions is remarkably small. Vie count Halimenites major, abundant in all 

 the localities of the Lower Lignitic. It has been found in the Cretaceous 

 underneath, and ascends in the Tertiary as high as Carbon. Sfquoia Langs- 

 dorffii, most common in the European Miocene, very rare at Black Buttes, 



