190 CALIFORNIA ACADEMY OF SCIENCIilS. 



descends a little, ten miles from SanKafael valley, into the 

 wide depression in the plateau in which the San Carlos 

 river flows, and follows this up to the summit, a distance of 

 about nine miles. The river here runs but little lower than 

 the general surface of the plateau, which necessitates very 

 rapid fall in the lower part of the course near San Kafael 

 valley. The upper part for nine miles from the summit has 

 a very inconsiderable fall; the water-course runs through a 

 series of swamps and little lakes, and heads in a somewhat 

 larger lake. There are no signs of glacial action. It is not 

 possible to see just where the divide is, so level is the gen- 

 eral surface of the country near the summit. For a few 

 miles eastward this character is preserved and then signs 

 of a more active erosion begin to appear. The pine forest 

 of the plateau disappears, the water-courses are worn doAvn 

 into gorges and canons walled in by white, abrupt, granitic 

 ridges; the country slopes rapidly. It is a wild landscape 

 of bare granite hills. Finally, climbing one of the ridges, 

 the spectator suddenly and unexpectedly finds a view ex- 

 tended before him which in grandeur and sublimity is sur- 

 passed by but few places on the continent. He stands at 

 the edge of a gigantic escarpment, descending about 3,000 

 feet in about five miles; naked granite cliffs, separated by 

 steep ravines and a few canons more deeply cut into the 

 rock form the face of this escarpment; at its base the Colo- 

 rado Desert spreads out, a dazzling white plain at the end 

 of which, fifty miles away, gleams the tide water of the 

 Colorado River at the Gulf of California. Again, far be- 

 yond this, may be seen the blue mountains of 'Arizona and 

 Sonora. 



The Colorado River, above the debouchure, is cut off from 

 view by a lower desert range, continuing N.N.W. and run- 

 ning east of the great Salt Lake Magnata, a blue sheet of 

 water on the white desert plain. 



The great escarpment, facing the desert, continues north- 

 ward and southward ; its general trend, however, is some- 



