NATURAL HISTORY OF THE DIATOMACE^. 469 



I have given in full all that Fremont says regarding this locality, as it 

 presents us with the first discovery of strata of the remarkable character 

 of which I am now treating, and is therefore of special interest. Bailey's 

 report, contained in the same volume, merely mentions and figures the 

 principal forms he detected. 



The only other description of this locality and these remarkable 

 deposits, fortunately, is a much more complete and scientific one. It is 

 that of Dr. J. S. Newberry, as geologist of the expedition under Lieuts. 

 R. S. Williamson and Henry L. Abbot, which explored the route for a 

 railroad, from the Sacramento valley to the Columbia river, in 1855, 

 and will be found in vol. vi of the Pacific Railroad Survey Report. Dr. 

 Newberry gives a description of the geology of the Des Chutes basin, 

 which is essentially as follows. It must be remembered that the Des 

 Chutes and Fall river, mentioned above, are one and the same. The 

 Des Chutes basin consists of a series of plateaus, having varying eleva- 

 tions from four thousand to twenty-two thousand feet above the level of 

 the sea, separated by subordinate ranges of volcanic mountains. These 

 plateaus are usually covered by a floor of trap, whicfi extends in a 

 smooth sheet from fifty to a hundred and fifty feet in thickness, un- 

 broken except by and at the canons of the various streams which, as a 

 general thing, flow from the interior to the ocean at right angles to the 

 coast line. Beneath this bed of trap is the whitish or light-colored 

 material, consisting of the siliceous remains of diatomaceae we are con- 

 sidering, sometimes occurring as a single bed only, sometimes as a series 

 of beds locally intercalated with thin beds of trap. These infusorial 

 strata, as they have been called, are cut in many places by the Des 

 Chutes and its tributaries to the depth of more than a thousand feet, 

 without exposing the basis on which they rest. They are usually quite 

 horizontal, from a few lines to twenty feet in thickness, and very accu- 

 rately stratified. 



Psuc-see-que creek, one of the tributaries of the Des Chutes river, 

 flows through a valley of a remarkable character, as its sides consist of 

 several alternate strata of diatomaceous material and columnar trap or 

 concrete. Near the base of this series of layers is a stratum, three feet 

 in thickness, of brilliant white feldspathic pumice, so soft as to be easily 

 crumbled in the fingers. Above, and lying upon this, is a line of dark 



