SKETCHES OF THE COLORADO DESERT 125 



Through the clay run strata, 1 to 6 inches in thickness, indurated 

 to stone, and burned to blackness by the heat. It is the broken 

 plates and shards of this claystone which, thickly coating the 

 upper parts of the mountains, give them their peculiar capped 

 appearance. Fragments, which the wind and sand have carved 

 into grotesque shapes, lie in lines along the outcrop of these 

 stfata. Many of the slopes glitter in the sunlight with bits of 

 plate g>"psum thickly imbedded in the brown clay. No marvel 

 that the Indian, beholding all these uncanny things, should 

 regard these mountains as the abode of evil spirits. 



The place was full of interest for the geologist or the ixiineralo- 

 gist, but to a botanist it was a disappointment. Not a single 

 plant, living or dead, was to be seen on any of the acclivities, 

 but in the wide ravines between grew a few stunted shrubs of 

 Atriplex canescens, and Parosela Emoryi, both common through- 

 out the desert. More abundant, and of greater interest, was 

 Ephedra trifurca, now for the first time found on this side of the 

 Colorado River. 



THE BOTTOM-LANDS OF THE COLORADO RIVER AT FORT YUMA 



The east-bound traveler approaches the Colorado River at 

 Fort Yuma over a planada of so slight an inclination as to appear 

 level. Thinly scattered over its else bare surface are stunted 

 larreas, and the tall rod-like stems of Fouquiera splendens. Along 

 the infrequent drainage channels, shallow and waterless, grow a 

 few dwarfed leguminous trees — Olneya Tesota and Cercidium tor- 

 reyanum. In the distance are long, rolling dunes, and ridges of 

 barren, sun-scorched mountains. 



It is but a slight drop from this scene of desolation to the 

 crowded jungle which borders the Colorado River for a width 

 of 1 to 3 miles. These bottoms are the uppermost extremity of 

 the great delta which the river has built, and is still building, by 

 the deposit of the silt with which its waters are heavily laden. 

 However familiar a botanist may be with other parts of Califor- 

 nia, he here finds himself in novel surroundings, for this delta 

 constitutes a distinct phytogeographical area, in which occur 

 plants not found elsewhere in the state. 



