120 HATCHER— OLIGOCENE AND MIOCENE DEPOSITS. [AprU 3, 



Northeastern Colorado," published as Part VII of Vol. I of the 

 Me7fioirs of the Atfierican Museum of Natural History , Dr. Mat- 

 thew has set forth additional facts in favor of his seolian theory as 

 to the origin of the deposits, which, if not furnishing conclusive 

 evidence as to the correctness of his theory, at least make it very 

 clear that the lacustrine theory is alone unable to explain many well- 

 known facts relating to the nature of these deposits and the distri- 

 bution, condition and nature of the animal remains found in them. 

 W. D. Johnson, in his paper on *' The High Plains and their Utili- 

 zation," published in the Twenty-first Annual Report of the United 

 States Geological Survey, has entirely ignored the lacustrine theory 

 of the origin of any of the Tertiary deposits of the plains, holding 

 that they are of fluviatile and flood-plain origin, while Dr. J. C. 

 Merriam, in a recent paper on "The Geology of the John Day 

 Basin," rejects the lacustrine theory of the origin of those deposits, 

 which had previously remained unquestioned. The above are the 

 leading authorities among those who have questioned the lake 

 theory as to the origin of these beds. On the other side the lacus- 

 trine origin of the rocks of the White River series, at least, has 

 been maintained by Todd, Scott, Darton and others, though 

 none of these authorities have thought it worth while to support 

 their contentions by the production of any considerable direct or 

 indirect evidence bearing on the case. Like the earlier writers they 

 have, almost without exception, set forth their views as if they were 

 well-established facts and beyond question or criticism. The fol- 

 lowing quotation from Scott is a fair example. In speaking of the 

 Oligocene series, on page 507 of his Introduction to Geology, he 

 says : '^ But in the interior regions are extensive fresh-water deposits 

 which clearly should be referred to it and which form the White 

 River stage. The largest body of water of this time occupied 

 northeastern Colorado, southeastern Wyoming, much of western 

 Nebraska and South Dakota." But the limits of this supposed 

 Oligocene lake have lately been greatly extended by Darton, who 

 has contended that it covered all of eastern and central Wyoming, 

 and a considerable portion of Montana and North Dakota'as well ; 

 so that one is at a loss to understand where lived the terrestrial 

 mammals and reptiles whose remains are now found in such abund- 

 ance in the deposits. 



The lacustrine theory had its origin in the until recently univers- 

 ally accepted idea that all sedimentary rocks showing stratification; 



