744 THE AMYZON BEDS. 



Green River. They have been greatly disturbed by the elevation of the 

 ranges bounding Humboldt Valley, as they dip nearly south, at an angle 

 of forty-five degrees, at the mine. 



The Tertiary shales of Florissant in the South Park of Colorado have 

 already yielded numerous species of plants, insects, and fishes, which have 

 been described by Messrs. Lesquereux, Scudder, and myself* Six species 

 of fishes have been determined, three of which pertain to the same genus 

 of Catostomidcr, which I had previously ptocured from the paper coal of 

 Osino, Nevada. On this ground, an approximation of the horizons of the 

 two localities was made. I have recorded the occurrence of a species of 

 the second genus found in the Osino coal, Trichophanes, of which the T. 

 Mans had been up to that time the only one known. The epochal identifi- 

 cation of the two formations was thus confirmed. 



The other species of fishes known belong to Amia, Amyzon Cope, and 

 Rhineastes Cope, members of the sucker and catfish families, respectively. 

 Both genera are nearly allied to existing forms, and the addition of the 

 Amia increases the modern facies of the ichthyic fauna of the period in 

 question. The discovery strengthens the evidence for the view that the 

 waters inhabited by these fishes were completely isolated from access of 

 salt or brackish water, thus differing from the beds of the Green River 

 epoch, and occupying a later position in the scale of periods. 



The regions of the John Day River and Blue Mountains furnish 

 sections of the formations of Central Oregon. Above the Loup Fork, or 

 Upper Miocene, there is a lava outflow, which has furnished the materials 

 of a later lacustrine formation, which contains man}' vegetable remains. 

 The material is coarse, and sometimes gravelly, and it is found on the Co- 

 lumbia River, and I think also in the interior basin. Professor Condon, in 

 his unpublished notes, calls this the Dalles Group.f It is in turn overlaid by 

 the beds of the second great volcanic outflow. Below the Loup Fork 

 follows the Truckee Group, so rich in extinct mammalia, and below this a 

 formation of shales. These are composed of fine material, and vary in 

 color, from a white to a pale brown and reddish-brown. They contain 

 vegetable remains in excellent preservation, and undeterminable fishes. 



•Bulletin U. S. Geol. Surv. Terrs. 1875, u. 1,3. 



tl have published this in the Proceedings of the American Philosophical Society 1880, p. 61. 



