AMERICAN MOUNTAINS. 377 



we shall ask the reader to look at as a whole and 

 as constituting but a single great range, though local 

 names have been assigned to various portions of it, 

 such as the Rocky Mountains, and its parallel range the 

 Cascade Mountains in Canada and the United States ; fur- 

 ther down in Mexico, it is called the " Sierra Madre " 

 or Mother Range, * and still further down in 

 South America the " Cordilleras de los Andes" or 

 great chain of the Andes. Mountain ranges as a 

 rule resemble very much in the general outline of their 

 ground plan the vertebra of a fish a herring bone 

 in fact the same sort of spurs or spines extending 

 from the main ridge on each side, as we see in the 

 case of a large fish bone. These spurs seem to 

 occur on all great mountain ranges, and often extend 

 out into the plains for very considerable distances. 

 Most of the great chains also consist of two or more 

 distinct ridges, running nearly parallel to each other, 

 and indicating, if we might venture to hazard a guess 

 on the subject, the existence of several lines of upheaval 

 acting in the same general direction. 



The Rocky Mountain system of North America for 

 example, is supposed to be " the result of four specially 

 marked upheavals; the first at the close of the car- 

 boniferous, the second at the close of the trias, the 

 third at the close of the cretaceous, and the fourth 

 during the tertiary epoch, " of which " the first and 

 third were the most general in their effects;" f 



* The word " Sierra " in Spanish, strictly translated means " a saw " 

 from the supposed resemblance between the teeth of a saw and the 

 jagged crests of the mountains. 



t The Origin of Mountain Ranges in relation to Geology and Historv 

 etc., by T. Mellard Reade, C.E., 1886, pp. 47 and 48. 



