AMERICAN GEOLOGY THE LARAMIE QUESTION. G57 



His conclusions, as summed up in his recapitulation of the Mesozoic, 



are as follows: 



The Laramie, by its own vertebrate remains, is proved to be unmistakably Cre- 

 taceous and the last deposit of that age, and it contains no exclusively fresh-water 

 life. Its plants resemble European Tertiary, but its Dinosaurs are conclusive of 

 Cretaceous age. It was the last of the conformable marine deposits of middle 

 America. Its latest period of sedimentation was immediately followed by an ener- 

 getic orographic disturbance, which closed the Mesozoic age. In that orographic 

 action the inter-American ocean was obliterated and the Cretaceous locally thrown 

 into great and steep folds. The following deposits over the Green River area were 

 fresh-water lacustrine lowest Eocene strata, lain down nonconformably with the 

 Cretaceous, except in accidental localities. 



In 1885 the problem was taken up by L. F. Ward in an exhaustive 

 paper on the Flora of the Laramie Group. This, although destruc- 

 tive in its criticism rather than decisive, nevertheless contained many 

 important suggestions. After a summary of opinions held by pre- 

 vious workers, he wrote: 



Taking all these facts into consideration, therefore, I do not hesitate to say that the 

 Laramie flora as closely resembles the Senonian ( Cretaceous ) flora as it does either the 

 Eocene or the Miocene flora, but I would insist that this does not necessarily prove 

 either the Cretaceous age of the Laramie group or its simultaneous deposit with any 

 of the Upper Cretaceous beds. The laws of variation and geographical distribution 

 forbid us to make any such sweeping deductions. With regard to the first point, it 

 is wholly immaterial whether we call the Laramie Cretaceous or Tertiary, so long as 

 we correctly understand its relations to the beds above and below it. We know that 

 the strata immediately beneath are recognized Upper Cretaceous, and we equally 

 know that the strata above are recognized Lower Tertiary. Whether the first inter- 

 mediate deposit be known as Cretaceous or Tertiary is, therefore, merely a question 

 of name, and its decision one way or another can not advance our knowledge in the 

 least. 



In this, it will be noted, he followed closely the opinions already 

 expressed by Hayden. 



Other statements of Ward's in this connection are worthy of consid- 

 eration. He pointed out that there was no probability that the condi- 

 tions existing during the Laramie deposition would be ever exactly 

 reproduced elsewhere, and hence the chances were as infinity to one 

 against the existence of other beds that should contain an invertebrate 

 fauna identical with that of the Laramie group. Further than this, 

 he regarded the law laid down by paleontologists that the same epochs 

 in geologic time produced the same living forms, as quite contrary to 

 the now well-established principles of geographical distribution. 



Amidst all this confusion and conflict of opinion, the fact was becom- 

 ing more and more apparent that under the term Laramie had been 

 included beds belonging to various but not widely separated horizons. 

 King and Hayden, it will be recalled, had believed it to contain all the 

 coal beds of the region in which it occurs and to be sharply circum- 

 xat mus 1904 42 



