AMERICAN GEOLOGY THE LARAMIE QUESTION. 651 



upon the flora, to the effect that the whole series of formations is of 

 Tertiary age, summed up his results as follows: 



J regard the evidence derived from the mollusks in the lower beds and the verte- 

 brates in the higher as equally conclusive that the beds are of Cretaceous age. There 

 is, then, no alternative but to accept the results that a Tertiary flora was contempo- 

 raneous with a Cretaceous fauna, establishing an uninterrupted succession of life 

 across what is generally regarded as one of the greatest breaks in geological time. 



Practically the same conclusion was independently arrived at by 

 Kingin his study of the Green River coal basin in connection with the 

 surveys of the fortieth parallel." He wrote: 



We have, then, here the uppermost members of the Cretaceous series laid down in 

 the period of oceanic sway and quite freely charged with fossil relics of marine life; 

 then an uninterrupted passage of coinformable beds through the brackish period up 

 until the whole Green River basin became a single sheet of fresh water. 



It will be seen then that the transitional character of the beds was 

 very generally recognized, the main point in dispute from now on being 

 that of their Upper Cretaceous or Lower Tertiary age. 



A. R. Marvine, in his report for this year (1ST:-)), also discussed the 

 problem, but somewhat guardedly, since his opportunities for obser- 

 vation had confessedly been somewhat limited. He wrote, after 

 summarizing the opinions of others: 



It must be supposed, then, that either a Cretaceous fauna extended forward into 

 the Eocene period and existed contemporaneously with an Eocene flora, or else 

 that a flora wonderfully prophetic of Eocene times anticipated its age and flourished 

 in the Cretaceous period to the exclusion of all Cretaceous plant forms. 



Again, and much more to the point, he wrote: 



Much of the confusion and discrepancy has, in my opinion, arisen from regarding 

 different horizons as one and the same thing. It must be distinctly understood that 

 tins group as it exists east of the mountains in Colorado is very different from, and 

 must not be confounded with, the horizon in winch much of the Utah ami New 

 Mexican lignite occurs, and which belongs undoubtedly to the Lower Cretaceous; 

 and, further, that the extended explorations of llayden and others would seem to 

 prove almost conclusively that the Colorado lignite group is the direct southern 

 stratigraphical equivalent of the Fort Union group of the upper Missouri, which is 

 considered generally to be no older than the Eocene, while Newberry asserts that it 

 is Miocene. 



To Lesquereux's conclusions in the report for 1872, Newberry, in 

 an article in the American Journal of Science, 1874, took exception, 

 calling in question the accuracy of many of his statements, and affirm- 

 ing that, to his "certain knowledge," a considerable portion of the 

 flora he called Eocene was really Cretaceous and another portion 

 Miocene. Further than that, having spent nearly two years in New 

 Mexican explorations, he felt authorized to state that all the lignite 

 beds yet known in New Mexico were unmistakably of Cretaceous age. 

 While, through lack of acquaintance with the Colorado localities cited 



"The third volume, 1870. 



