SAN RAFAEL SWELL 19 



Green River and the Wasatch Plateau. All these had their inception in 

 Miocene time except the one around the Grand Canon, which goes back 

 into the latter part of the Eocene. This gradual dissolution of the strata 

 by the waste of their edges constitutes what Powell has called the Recession 

 of Cliffs. 



Of these five centres of maximum erosion, the San Rafael Swell is by 

 far the best suited for study, and may be regarded as the type of them all. 

 If we stand upon the eastern verge of the Wasatch Plateau and look east- 

 ward, we shall behold one of those strange spectacles which are seen only 

 in the Plateau Province, and which have a peculiar kind of impressiveness, 

 and even of sublimity. From an altitude of more than 11,000 feet the eye 

 can sweep a semicircle with a radius of more than 70 miles. It is not the 

 wonder inspired by great mountains, for only two or three peaks of the 

 Henry Mountains are well in view; and these, with their noble Alpine 

 forms, seem as strangely oiit of place as Westminster Abbey would be 

 among the ruins of Thebes. Nor is it the broad expanse of cheerful plains 

 stretching their mottled surfaces beyond the visible horizon. It is a pic- 

 ture of desolation and decay; of a land dead and rotten, with dissolution 

 apparent all over its face. It consists of a series of terraces, all inclining 

 upwards to the east, cut by a labyrinth of deep narrow gorges, and 

 •sprinkled with numberless buttes of strange form and sculpture. We stand 

 upon the Lower Tertiary, and right beneath our feet is a precipice leaping 

 down across the edges of the level strata upon a terrace 1,^00 feet below. 

 The cliff on which we stand stretches far northward into the hazy distance, 

 gradually swinging- eastward, and then southward far beyond the reach of 

 vision and below the horizon. It describes, as we well know, a rude semi- 

 circle around a centre more than 40 miles to the eastward. At the foot of 

 this cliff is a terrace about 6 miles wide of Upper Cretaceous beds, inclining 

 upwards towards the east very slightly, and at that distance it is cut off by 

 a second cliff, plunging down 1,800 feet upon Middle Cretaceous beds. 

 This second cliff describes a smaller semicircle like the first and concentric 

 with it. From its foot the strata again rise gently towards the east through 

 a distance of 10 miles, and are cut off by a third series of cliffs as before. 



