COLOKADO DESERT MOUNTAIN RANGES — EARTHQUAKES. 105 



Sierra de San Pedro, a solid rock many feet in height, and resembling the dome of a cathedral. 

 Some god is supposed to inhahlt this range. Near it is a second peak, called the '' broken dome." 

 To the east, and extending south, are Cone mountain, of the Santa Isabel range, and the Sierra 

 de la Gila ; Antelope peak is the principal one of the latter. To tlie soutlieast, mountain after 

 mountain rises up ; to the south, those of Lower California are plainly visible, so high that 

 snow envelopes their tops ; and when the southwest winds blow, they are more chilly than those 

 from the north, bearing along with them the cold air of the snow-clad peaks. From a distance 

 these mountain ranges look rugged in the extreme, although here and there, as you watch the 

 play of the sun, you see reflected back perpendicular walls of smooth, white rock. 



The atmosphere is so clear that you are able to see at long distances. In the morning a 

 beautiful sight is afforded by the mirage. It has the effect, apparently, of raising tlie mountains 

 and bringing them more plainly to view, and many are the fantastic and peculiar shapes that 



are represented. 



We turn from this barren view and look with pleasure upon the bright green foliage which 

 marks the course of the Colorado. The river-bottom, varying in width, is generally brond and 

 feitile— an alluvial deposite, covered with a thick growth of timber. Large cotton-wood trees, 

 different varieties of willow thickly matted together, and impenetrable thickets of arrow and 

 grease-wood, grow near the river ; further back the mezquite of two kinds— the flat-pod and 

 the screw-bean— thrive and flourish. The bottom is intersected by innumerable lagoons and 

 sloughs, which during the annual rises fill to overflowing, and irrigate the soil. The earth is 

 consequently impregnated with the salts of potash, magnesia, and soda, which are held in 

 solution by the water. No vegetation will grow beyond the influence of these overflows, and 

 when a white efflorescence appears upon the surface of the ground it is useless to plant, as 

 nothing edible for man or beast will grow there. 



The delta of the Colorado and Gila is below high-water mark, and is subjected to overflows. 

 The soil is a mixture of clay and sand. There are some few varieties of grass very scatteringly 

 distributed. The distance from Fort Yuma to the mouth of the Colorado is about one hundred 

 and sixty miles. The whole of the country strongly resembles the Rio Bravo del Norte in the 

 general appearance of its vegetable forms ; varieties of cacti, the maguey plant, Larrea Mexicana, 

 and the fouquiera, are all found here. Although both regions are probably of the same geological 

 structure, they are not equal in richness, that upon the Rio Grande being the most fertile. To 

 add to the interest of this section of our land, we find it is subject to earthquakes, by which it is 

 sometimes depressed and sometimes elevated. To quote from a very interesting account given by 

 Major Heintzelman of a visit made to the scene in November, 1852, he says : " The low ground was 

 full of cracks, from many of which there gushed forth sulphurous water, mud, and sand. At 

 the time, great changes were made in the river-bed. The earthquake appears to have been 

 occasioned by an accumulation of gases and steam in the caverns of the earth. The elasticity 

 of these forced an escape through a pond forty-five miles below, on the desert between the river 

 and coast mountains, the repeated escapes causing rumbling and shocks. It is an old orifice, 

 that has been closed several years, so that the first effort occasioned the most violent explosion. 



The steam 



This 



appearing above the tops of the mountains like a white cloud, and gradually disappeared, 

 was repeated several times, but on a much smaller scale." ^ 



When theMajor visited the place three months later, " these jets took place at irregular intervals 

 of fifteen or twenty minutes, and had a beautiful effect as they rose, mingled with the black 



Vol. I 14 



