52 GEOLOGICAL SURVEY OF THE TEERITOEIES. 



" As the Cretaceous fishes are more nearly related to the Tertiary than 

 to the Jurassic fishes, the Upper Cretaceous florals also entirely different 

 from the Jurassic and more nearly allied to the Tertiary floras, and it ap- 

 pears that in America the relation between the Tertiary and Cretaceous 

 floras is yet more intimate than in Europe. 



" It is remarkable that the plants of Nebraska (as Magnolia and £iri- 

 odendron) present relations with the existiug flora of America, while 

 the Cretaceous flora of Europe has more of an Indo-Australian character. 

 It thus appears that since the Cretaceous epoch the American flora has 

 not undergone a change so great as the European flora. While the Cre- 

 taceous flora of Europe is entirely difl'erent from the existing European 

 flora, that of Nebraska contains eight genera yet found in America, and 

 it is the more remarkable that the greater part are yet found in a coun- 

 try under the same latitude." 



Professor Heer describes the following species of plants from this 

 group in this memoir : 



Populus litigiosa, (f) Deheyana, Salix nervillosa, BetuUtes denticidata, 

 Ficus ])rimordialis, Flatanus (?) newherryana, Froteoides grevilleceformis, 

 F. daphnegenoides, F. acuta, AristolocMtes dentata, Andromeda parlatorii, 

 Diospyrus primcevus, Cissites insignis, Magnolia alternans, M. capellini, 

 Liriodendron meekice, Fhyllites vanonce. 



One instructive lesson is derived from the mistakes of these eminent 

 men that, in the progress of geological development, America was almost 

 or quite one epoch ahead of Europe — that the fauna and flora of the 

 Cretaceous period in this country were really more nearly allied to those 

 of the Tertiary period in Europe, and that, geologically speaking, 

 America should be called the Old World and Europe the New. This 

 point will be again alluded to in our remarks on the Tertiary rocks. 



Again, there is evident simplicity in the form and ornamentation of 

 these leaves, which marks the dawn of the appearance on this planet of 

 trees like our forest, fruit, and ornamental trees. 



The beauty of foliage in our present dicotyledonous trees is largely 

 due to the serrations and various forms and patterns which they present ; 

 but, so far as my observations have extended, the reverse is the case 

 with this Cretaceous vegetation for the most part — thus slowly progress- 

 ing through the Tertiary period from simplicity up to greater complexity 

 and beauty. 



The question would arise naturally, Have any remains of land animals 

 been found in this group mingled with these vegetable imi^ressions ? 

 None have yet been observed along the Missouri at this locality; and as 

 they have now been studied with considerable care, we may never find 

 any. That land animals did exist we cannot doubt, for the forests which 

 furnished these leaves could not have existed far away. 



The leaves are so perfect that they could not have been transported 

 to a great distance before they were imbedded in the sand. On the 

 eastern slope of the Big Horn Monntains there are a series of beds which 

 hold a position between the Jurassic beds and the Fort Benton group, 

 which I have referred to the Dakota group. 



Here occur beds of impure earthy lignite, large quantities of silicified 

 wood and uncharacteristic bones, which Dr. Leidy thinks belonged to 

 some huge saurian. No remains of strictly land animals have ever beeu 

 found. 



The geographical extension of this group of rocks outside of this State 

 has been found to be very extensive. The belt of country occupied by 

 them in Nebraska runs nearly southeast and northwest, and is from 60 

 to 80 miles wide, extending far south into New Mexico, and possibly 



