AGE OF THE LIGNITIC DETERMINED BY ITS FLORA. 339 



would he more (lian sufficient to authorize tlie conclusion that the llora of 

 the Lower Lignitic is positively Tertiary in its characters. But, as; com- 

 parisons made from an exposition like that of the table have generally more 

 or less of ambiguity, and can but leave some doubt or distrust on the value 

 of the conclusions, it is advisable to look somewhat deeper into the subject, 

 and to see on what kind and degree of relation is based the assertion that 

 the flora of the Lower Lignitic is of Tertiary age. 



The marine plants might perhaps be omitted, as have been the Lichenes 

 and the Fungi, in a comparison like the one we have to make; for their distri- 

 bution is too wide and their characters too uncertain. The relation of Hali- 

 menites major, for example, which is so profusely found in connection with 

 the Lower Lignitic sandstone of Colorado and Wyoming, seems to be quite 

 as distinctly marked with the Cretaceous as with the Tertiary; for Count 

 Saporta has a closely allied form described from the Jurassic, and Prof Meek 

 has found the identical species at Bear River in strata which he considers 

 positively Cretaceous from the determination of their invertebrate remains. 

 We have, however, to admit a degree of evidence from the predominance of 

 Fucoidal remains in the Lower Lignitic, as equally remarked in the Eocene 

 of Europe, especially of Switzerland. Indeed, it was from the profusion of 

 the so-called Fucoids,in the Lower Lignitic sandstone of the Raton Mountains 

 that I received the first indication of the Eocene relation of this formation. 

 The presence of Delesseria species in the lower sandstone at Golden was a 

 confirmation of the first impression; for, of the eight species of Delesseria 

 described by European authors, seven are Eocene. 



Leaving out of count the Fucoids, we have the Lycopod'iacece^ a family 

 whose presence is already recorded in the oldest chronicles of the fossil floras 

 of the world, those of the Silurian, and which is especially predominant in the 

 Carboniferous epoch, where its species, mostly large trees, have contributed, 

 with tlie Ferns and the Calamarioi^ the essential part of the compounds of the 

 coal. But from the base of the Permian, the LycopodlacecB seem to disappear 

 completely; for nothing referable to them has been found in the subsequent for- 

 mations, but two uncertain forms in theOolite of 'England , Lijcopodites unc/folius 

 and L. falcatus, LI. & Hutt., plants whose relation has always been con- 

 sidered as doubtful; as, until now, no species of this order has been 

 described from the Cretaceous and the Tertiary. This disappearance has 

 been a fact the more inexplicable, that the Lycopodiacca are mostly of hard, 



