272 
THE WASATGH FAUNA. 
American Tertiary formations, since it otfers a point of departure for the 
estimation of the relations of the preceding and succeeding faunse. It is 
additional evidence in favor of the Upper Cretaceous age of the strata, 
which, in Wyoming and elsewhere, immediately underlie them, viz, the 
Bitter Creek, or, what may be the same, the Fort Union Lignite beds. It 
appears also that the resemblance of the North American and European 
Vertebrate faunse was closer during the Suessonian epoch than at any subse¬ 
quent period of Tertiary time. A divergence took place, which is stronglj^- 
marked in the Lower Miocene (White River) and Upper Miocene (Loup 
Fork) faunse, especially in the former. See the report on the latter in the 
last chapter of this volume. 
The Wasatch formation includes the Green River beds of Hayden, a 
name which I formerly applied to the ■ entire series. It, however, applies 
properly to the fish-shales of Green River, containing Asineops, Clupea, 
Osteoglossum, etc., which are probably local in their character. Professor 
Lesquereux* remarks that “ the remains of plants at Green River are found 
in laminated shales, with an abundance of skeletons of fishes”. These plants 
he had alreadyf assigned to the Miocene period, and in the former report 
to Dr. Hayden, says of the flora:} “If it had not so many typical represent¬ 
atives of the Miocene of Europe, and if, at the same time, it had some of 
our living species, it might be considered as Pliocene.” Thus it appears 
that the testimony of the plants conflicts with that of the animals in the 
question of the age of this horizon, as it does in the case of the Fort Union 
(Lignitic) beds, and in the same direction. Thus what I call Cretaceous 
and Lower Eocene, Professor Lesquereux calls Eocene and Upper Miocene 
Tertiary respectively. The obvious conclusion is, what is indeed already 
well known, that the existing flora has a greater antiquity than the existing 
fauna, and that this has been the case throughout the later periods of geo¬ 
logic time. This is consistent with the discovery, by Dr. Hector, in New 
Zealand, that the existing flora of that island dates from the Jurassic period. 
I may add, however, in reference to the age of the Suessonian forma¬ 
tion, with which I have parallelized the Wasatch (and Green River) epoch, 
* Ann. Kept. U. S. Geol. Surv. Terrs., 1873, p. 390. 
t Loc. cit., 1872, pp. 410-416. 
I Loc. cit., 1873, p. 390. 
