1902.] HATCHER — OLIGOCENE AND MIOCENE DEPOSITS. 125 



in a somewhat modified form the theory advanced by him, 

 extending his observations and adding certain additional facts 

 observed by the present writer and bearing directly upon the 

 subject. 



Matthew's theory as to the origin of these deposits may best be 

 described in his own language. Speaking of the conditions attend- 

 ing the deposition of these beds, he says : " The nature of the 

 organic remains, where such have been found, seem to definitely 

 negative the idea of any vast lake, and to favor less the theory of a 

 series of lagoons and swamps than that of a broad, open and com- 

 paratively level plain, with shallow, probably wooded, rivers 

 meandering over parts of it and deposits partly or chiefly brought 

 by rivers, but in large part redistributed over the higher sodded 

 grassland by the agency of the wind." With most of the 

 principal features of this theory as applied by its author the present 

 writer is in accord. I believe, however, that the materials on the 

 whole partake more of the nature of fluviatile and flood-plain 

 deposits than of those characteristic of prairie loess. 



Paleontological Evidences. 



The distribution, state of preservation, nature and character of 

 the animal and plant remains found in the clays and sandstones, as 

 well as the distribution of the latter, absolutely preclude the possi- 

 bility of their having been deposited in a vast lake and favor the 

 presence of streams meandering through low, broad, level, open or 

 wooded valleys subjected in part at least to frequent inundations, 

 conditions very similar to those at present prevailing in the interior 

 of South America, about the headwaters of the Orinoco, the 

 Amazon and the Paraguay and Parana Rivers. 



Now it is evident that if such conditions prevailed in this region 

 during the deposition of the White River beds there should remain 

 certain evidences concerning it, such as filled-in river channels and 

 small lagoons with their characteristic deposits and remains of the 

 animal and vegetable life peculiar to each. Moreover some indica- 

 tion at least of the forests should remain and be found somewhere 

 in this vast region. With these and many other points constantly 

 in mind the writer passed a considerable portion of the seasons of 

 1900 and 1 90 1 in exploring these deposits. Particular attention 

 was given to ascertaining whether or not they contained an aquatic 

 fauna and flora. The sandstone lenses were especially examined 



