104 Remarks on the Cretaceous and [February, 



cal species, and the affinity of character of a Pterophyllum, a Cau- 

 linites, a Fagus, two species of Ficus, a Myrica and a Daphnogene. 



To set aside the evidence derived from the remains of plants 

 indicating synchronism and Cretaceous age of the localities above 

 named, it may be said, as it has been done for the Laramie 

 group, that vegetable remains are not sufficient authority for the 

 determination of the age of a formation. 



But here the determination of the formation from where the re- 

 mains are derived, has been first made, or later confirmed by the 

 characters of animal remains found in the intercalated or superposed 

 strata. Heer states that the Moletin formation is positively referable 

 tothe quader-sandstone, Cenomanian, overlying the planer of Reuss 

 referred to the Turonian ; and of that of Quedlinburg, he states 

 that it is referable to the lowest zone of the Belemnitella quadrata, 

 which constitutes the lowest stage of the Senonian or Upper Cre- 

 taceous. In the quader-sandstein of the Hartz, from where the 

 Credneria species have been obtained, a large number of animal 

 remains, mostly of invertebrate and fishes, have been found. 

 Stiehler, in his Beitrage, 1 quotes a long list of these genera and 

 species, all Cretaceous. It is the same with the animal remains 

 found in the strata overlaying the Dakota group in a space of 

 more than two thousand feet. 



The objection by Mr. Gardner is, that these so-called Creta- 

 ceous animal remains may not or are not generally or specifi- 

 cally identical with those of the Middle Cretaceous of Eng- 

 land. Of this I am unable to judge. But it is said also that 

 the vegetable types of the Dakota group appear too young to 

 represent a Cretaceous formation, for some of them are closely 

 related to plants of the Miocene. This is true, as it will be 

 seen here below ; but that cannot be taken into account in the 

 discussion, for the relation is quite as prominent, rather still more 

 marked with species of the present vegetation of North America, 

 where a number of types of the flora of the Dakota group are 

 reproduced in some of the more important and beautiful trees of 

 our forests. This is the more remarkable that the affinity is not 

 at all observable with the plants of the Lower Tertiary or Eocene 

 of the Laramie group. But this refers to the second part of the 

 discussion ; before coming to it there are still a few words to say 

 on the present objection. 



1 Beitrage zur Kentnis-; <ler Vorweltlichen Flora, 1857. 



