AMERICAN GEOLOGY THE LARAMIE QUESTION. 653 



least one fossil identified with the Cretaceous, and a few of which were 

 identical with European species. 



It was more reasonable, he thought, to suppose that in the later 

 portion of the Cretaceous period the climate in our northwestern 

 region was like that of the European Eocene than to imagine that our 

 Cretaceous fauna is useless for determination of horizon in the narrow 

 .-trip east of the mountains in Colorado, while acknowledging it to be 

 decisively of Cretaceous age in New Mexico, the rocks being the same, 

 but the leaves being absent. 



To Newberry's criticisms Lesqucreux replied" that the Cretaceous 

 age of the so-called halymenites sandstone had not yet been proven 

 and could not be decided on mere affirmation; but that when Doctor 

 Newberry had furnished sufficient proof or evidence on the geological 

 age of the lignites of New Mexico he was prepared to accept Ms deci 

 sion. The quoted opinions of Marsh. Cope, and Stevenson he claimed 

 were based on insufficient evidence. All the repeated assertions of 

 the finding of fossil shells and bones of Cretaceous age in the lignites 

 of Colorado, when carefully sifted down, reduced themselves to the 

 finding of a single badly -preserved specimen of Inoceramus. 



He asserted that the lignitic formation, having positively a pre- 

 ponderance of land plants over marine animals, in other words, being 

 composed wholly of detritus from the land or a land formation, as he 

 styled it, the evidence presented by the fossil plants should outweigh 

 in importance that of some Cretaceous animal remains, whose presence 

 could be considered as of casual occurrence. Cope's conclusions, he 

 argued, did not in the least interfere with his own, simply proving the 

 noncoincidence of animal and vegetable types in certain formations, 

 but if, he added: 



Tertiary and Cretaceous faunas are regarded as contemporaneous, even inhabiting 

 the same repositories, we may more easily admit that a Cretaceous fauna and Ter- 

 tiary flora have sometimes succeeded each other in alternating strata. 



Lesquereux further contended that the specimens on which Doctor 

 Newberry had relied to substantiate the sum of the opinions he 

 advanced had become mixed and had, in reality, come from different 

 localities and represented different horizons. 



In his report for 1874 (letter of transmittal written in October, 

 isTo) Hayden took up the matter once more, with particular reference 

 to the results of investigations in Colorado. These he felt warranted 

 him in drawing the following conclusions: 



First. That through the upper portion of the Fox Hill group (Cre- 

 taceous) there are clear proofs of a radical physical change, usually 

 with no break in the sequence of time. In this portion of the group 



"American Journal of Science, L874. 



