XV'i GEOLOGY OF THE HIGH PLATEAUS. 



intimate relations. In the brief season during which work in such a region 

 is practicable the investigation must be pushed with the utmost vigor and 

 rapidity, and the greatest portion of the time must be devoted to acquiring 

 a general and connected view of the broader features, while details cannot 

 often receive the attention which their importance really demands. From 

 the nature of the case, therefore, the work must be somewhat superficial in 

 many respects. 



In preparing a monograph upon this district, it has been necessary to 

 lay the greatest stress upon a few subjects of inquiry, and these would natu- 

 rally be those which the facts most fully exemplify. It was important, 

 however, at the beginning to discuss it as a part of a great geological prov- 

 ince, in which are found certain categories of facts possessing a peculiar 

 interest, displayed in a remarkable manner, and of the highest importance 

 to physical geology. The "Plateau Country" of the west is, I firmly 

 believe, destined to become one of the most instructive fields of research 

 which greoloo-ists in the future will have occasion to investigate. Of its sub- 



DO O 



divisions the District of the High Plateaus is one of the most important, 

 and the relations of the district to the province were studied with great care. 

 The results of those studies are set forth in general terms in the first two 

 chapters. 



In the treatment of geological phenomena occurring within the district 

 the investigation has been devoted chiefly to three lines of inquiry. The 

 first is geological structure — those attitudes of the strata and the topo- 

 graphical forms which have been caused by the vertical movements of the 

 rocks. The displacements which have occurred there are very striking 

 both in respect to their magnitude and to their systematic arrangement. In 

 their forms and modes of occurrence they are also somewhat peculiar, 

 especially when brought into comparison with displacements found in other 

 regions. Ultimately such facts must take their place in that branch of 

 geological philosophy which treats of the evolution of the earth's physical 

 features, the building of mountains, and the elevation of continents and 

 plateaus; but at present the observed facts do not appear to group them- 

 selves into the relation of effects to causes. The broader facts relating to 

 structure are discussed in the second chapter. 



