No. 1.] CEOLOGt AND MINERALOGY. 115 



gave me my first hint of the true history of these deposits. These, 

 collected on the head waters of Pit River, the Klamath, Des 

 Chutes, Columbia and elsewhere, were transmitted for examination 

 to Professor Bailey, then our most skilled microscopist. Almost 

 the last work he did before his untimely death was to report to me 

 the results of his observation on them. This report was as har- 

 monious as it was unexpected. In every one of the chalk-like 

 deposits to which I have referred he found fresh-water diatomaceae. , 



From the stratification and horizontality of these deposits, I 

 had been fully assured that they were thrown down from great 

 bodies of water that filled the spaces separating the more elevated 

 portions of the interior basin, and here I had evidence that this 

 water was fresh. Since that time a vast amount of evidence has 

 accumulated to confirm the general view then taken of the changes 

 through which the surface of this portion of our continent has 

 passed. From South-western Idaho and Eastern Oregon I have 

 now received large collections of animal and vegetable fossils of 

 great variety and interest. Of these the plants have been, for the 

 most part, collected by Rev. Thomas Condon, of the Dahll, 

 Oregon, who has exposed himself to great hardship and danger by 

 his several expeditions to the localities in Eastern Oregon, where 

 these fossils are found. The plants obtained by Mr. Condon are 

 apparently of Miocene age, forming twenty or thirty species^ 

 nearly all new and such as represent a forest growth as varied and 

 luxuriant as can be now found on any portion of our continent. 



The animal remains contained in these fresh-water deposits 

 have come mostly from the banks of Castle Creek in the Owyhes 

 district, Idaho. The specimens I have received were sent me by 

 Mr. J. M. Adams, of Ruby City. They consist of the bones of 

 the mastodon, rhinoceros, horse, elk, and other large mammals, of 

 which the species are probably in some cases new, in others 

 identical with those obtained from the fresh-water Tertiaries of 

 the * Bad Lands ' by Dr. Hayden. With these mammalian 

 remains are a few bones of birds and great numbers of the bones 

 and teeth of fishes. These last are Cyprinoids allied to Mylop- 

 harodon, 3ItIochsilus, etc., and some of the species attained a 

 lensjth of three feet or more. There are also in this collection 

 large numbers of fresh-Water shells of the genera Unio, Corhicula^ 

 Melania and Planorhis,'^ All these fossils show that at one 



* One of the mo^t commou is a species of Tiara closely resembling an 

 East Indian one, while the genus no longer exists in this continent. 



