Geology from a Motor Car 



Miniature Volcanoes in Action 



It will be well if time will permit to rest at the Barbara 

 Worth Hotel and make side excursions to points of interest, the 

 like of which will not be likely to be seen anywhere else. Mud 

 geysers occur along the axis of the valley from Imperial Jet. 

 (Niland) south to Volcano Lake in Mexico. Innumerable 

 small mud cones, solfataras, and boiling pools of mud and water 

 emit steam, smoke and sulphurous gases, accompanied by a dull 

 rumbling sound. The "dry ice" plant is a little way off the 

 main highway. Here the natural gas (carbon dioxide) is 

 caught as it escapes from a well, and carloads of ice that will 

 blister your hands if you touch it are shipped out. 



Shore-Line of Lake Cahuilla 



Proceeding north along the shore of the Salton Sea, an 

 eroded ridge, the beach or shore-line of ancient Lake Cahuilla 

 (see Chap. IX) will be observed at many points at the left. 

 This old beach line is about 40 feet above sea level. The level 

 plain over which we are passing is the ancient lake bottom. 

 The present Salton Sea, from which the evaporation is at the 

 rate of more than seven feet per annum, whereas the annual 

 precipitation is less than three inches per year, lies in the axis 

 of the ancient lake bed. 



Fossils in Rocks of Carrizo Mountain 



Superstition Mountain, 15 miles west of Brawley, rises 764 

 feet above the ancient lake bottom. It is a granite core sur- 

 rounded by low hills of sandstone and clay (the latter of Ter- 

 tiary age) . Carrizo and Black Mountains, called also Coyote 

 and Fish Creek Mountains, west of Superstition Mountain, are 

 outliers of the Peninsular Range. They are islands of granitic 

 and metamorphic rocks, which rise through encircling terranes 

 of sedimentary and volcanic rocks of Miocene or later Tertiary 

 age. The unconformity between these later deposits and the 

 granitic bed-rock is very marked, but it is necessary to depart 



