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AGE OF THE LIGNITE FORMATION. 189 
441. Prof. Meck, early in the field, concurs with Hayden, as we have 
seen, in 1857, in ascribing the lignite strata to the Miocene. As early as 
1860, it would appear, however, that he had referred some molluscs from 
the lower part of the coal-bearing series to the Cretaceous, and in 1870 
he takes the view that the beds of Bear River and Coalville in Utah, 
are Upper Cretaceous, passing up through a series of transition strata to 
Eocene ; though he is at the same time careful to guard against the 
supposition that he considers the limits of either one formation or other, 
to be exactly synchronous with those of the same names, and typified by 
similar fossils in Europe.* Reasoning entirely from the results of his 
examination of the invertebrate fossils, he places the lower beds, con- 
taining undoubted marine forms in the Upper Cretaceous, assigning 
them a position superior to Cretaceous No. 5, of the typical sections, 
Those with estuarine forms, are referred to the Tertiary; though in the 
conclusion of a note, on fossils submitted to him by Mr. Clarence King, 
he remarks :—“ While I am, therefore, willing to admit that facts may 
yet be discovered that will warrant the conclusion that some of the 
estuary beds, so widely distributed here, should be included rather in 
the Cretaceous than in the Tertiary, it seems to me that such evidence 
must either come from included Vertebrate remains, or from further 
discoveries respecting the stratigraphical position of the beds with 
relation to other established horizons, since all the molluscan remains 
yet known from them seem to point to a later origin.” + The most 
typical Cretaceous forms recognised in the marine beds are, Inoceramus, 
Anchuria and Gyrodes, “Genera that seem not to have survived the 
close of the Cretaceous period.” t Several other fossils of Cretaceous 
aspect, however, occur, and in some cases are compared specifically with 
those of the higher Cretaceous beds of California. § In summing up his 
arguments for the Cretaceous age of the lower beds of the Green River 
Basin, Prof. Meek lays especial stress on the occurrence of IJnoceramus, 
and asomewhat doubtful specimen of Anchuria, and also on the fact that 
_ there is no evidence of the existence of any strictly marine Tertiary deposits 
in the interior region of the continent. He admits that if the remainder of 
the molluscous fauna were presented to any paleontologist unaware of 
the existence of the Cretaceous forms mentioned, and the generalization 

* See Prof. Meek’s very interesting review of the question in U.S. Geol. Sur. Territ., 1870, pp. 
290, 291. t U.S. Geol. Exploration Fortieth Parallel ; vol. 11., 1870, p. 466. 
s { U. S. Geol. Surv. Territ., 1870, p. 290. 
§ The inclusion of remains derived from the disintegration of older but unconsolidated beds may ac- 
count for some of these facts. In the drift clays of the western plains, I have seen little altered 
Cretaceous shells imbedded, in a manner which would have been very puzzling, had their Cretaceous 
affinities not been known. 

