76 GRAND CANON DISTRICT. 



cessively appearing until upon the flanks of the Uintas we find the 

 whole Eocene series in enormous volume, exceeding perhaps 5,000 feet. 

 Could these middle and Upper Eocene masses once have existed upon 

 the southern portion of the High Plateaus and been swept away by 

 erosion? There is strong evidence to the contrary.* The facts, then, 

 indicate that when the desiccation of thelake took place, the portion which 

 first emerged was the southern and southwestern — or the Grand Canon 

 district; that its shore line gradually receded northward during middle 

 and upper Eocene time, leaving dry land behind it ; and the last remnant 

 of the lake disappeared near the base of the Uintas. Wherever the physi- 

 cal geology and evolution of the Grand Canon district touches the ques- 

 tion of time, the earlier date of its emergence than that of other portions 

 of the Plateau Province appears — sometimes dimly, sometimes forcibly. 

 The principal mass of the Eocene terminates at the " Pink Clill's," as 

 they are called, in the southern margins of the Markagunt and Paunsa- 

 gunt Plateaus. There are a few outliers beyond. Around the base of 

 the Pine Valley Mountains to the southwest, and beyond them in the 

 same direction, some remnants have escaped destruction. But this part 

 of the country has not been sufficiently explored to indicate more than 

 the bare fact of their existence. Far to the eastward a single outlier 

 stands upon the summit of the great Kaiparo wits Plateau, forming the 

 apex of Kaiparowits Peak. But generally speaking, the Eocene is 

 wholly absent, so far as known, from the country south of the terraces. 



THE CRETACEOUS. 



The platform immediately below the Pink Cliffs is picturesque rather 

 than grand. Rough rolling ridges of yellow sandstone, long sloping 

 hillsides, and rocky promontories clad with large pines and spruces, sur- 

 round the valleys. These rocks are of Cretaceous age. Upon the south- 

 ward slopes of the Paunsagunt and Markagunt Plateaus, they nowhere 

 present the serried fronts of cliffs, but break down into long irregular 

 slopes much like those of common hill countries. In those superficial 

 and merely scenic aspects which make the terraces so impressive, the 

 Cretaceous is for the most part notably deficient ; but in those deeper 

 studies, which are of most significance to the geologist, it holds an im- 

 portance not inferior to that of any other formation. It is never wanting 

 at its proper place in the terraces, but always displays a vast series of 

 sandstones and clay-shales, varying from 4,000 to 5,000 feet in thickness. 

 Around the western and southern Hanks of the Markagunt, and just 

 beneath the summit platform, they occupy a belt varying in width from 

 4 to 10 miles. Around the Paunsagunt their relative positions and re- 



*This evidence will be fully discussed in my monograph on the Geology of the Grand 

 Canon district. — C. E. D. 



