SECTION THROUGH JOHN DAY BASIN 497 



formation is made up entirely of tuffs, ashes, and lavas. In places it contains many 

 plant remains and is apparently in part a fresh- water formation. 



The John Day formation rests directly upon the Clarno at Clarnos ferry. The 

 basin in which it was deposited is quite different from that of the Clarno. It prob- 

 ably rests unconformably upon that formation. The Lower Johli Day beds are 

 considerably contorted in some localities. Ordinarily they are colored a dee{) red. 

 Fossil remains are exceedingly rare in this division. 



The blue-green beds of the Middle John Day are very fossiliferous. They corre- 

 spond to the Diceratherium beds of Wortman. The Upper or Buff beds of the John 

 Day lap over the middle division and rest in places upon the older formations. 

 The upper division corresponds to the Merycochoerus beds of Wortman. As Mery- 

 cocJioerus does not occur in the John Day, the upper division will be called the Para- 

 cotylops beds. This name is based on the new generic name proposed by W. D. 

 Matthew for the Upper John Day oreodons, originally sui)posed to be Merycochoerus. 



The Columbia lava, an extension of the lavas on the Columbia river to the north, 

 rests unconformably on the crumpled John Day formation. The name Columbia 

 lava should be restricted to this horizon of the lavas in this region, as other beds 

 included in this group belong in some cases to different geological periods. 



The Cottonwood (Loup Fork) formation, near 1,000 feet in thickness, rests on the 

 Columbia lava. The Van Horn Ranch plants, which have generallj'^ been consid- 

 ered as John Day, are from this horizon. Remains of a true John Day flora, which 

 had not previously been known, were discovered by the University of California 

 expedition in 1900. The discovery of the true stratigraphic position of the Van 

 Horn Ranch flora explains the apparent inverted position of the Neocene forma 

 tions in central Wasiiington. 



Resting on the worn edges of the Cottonwood beds is the Rattlesnake formation, 

 comprising several hundred feet of gravel, tuff, and lava. 



In canyons cut through the Rattlesnake and Cottonwood are several terraces. 

 Remains of elephants and later horses found in the lower terrace deposits show 

 that they were formed in Quaternary time. 



The Section then adjourned to meet at the same place at 10 o'clock 

 the following morning, the exhibition of slides illustrating Doctor Mer- 

 riam's paper being postponed till that time. 



Session of the Cordilleran Section Saturday, December 29 



The Section met at 10 a m in the rooms of the Geological Department 

 of the University of California, the chairman-elect, Professor Knight, in 

 the chair. 



Dr J. C.-Merriam exhibited the lantern slides illustrating his paper. 

 The following papers were then read and discussed : 



