RELATIVE HEIGHTS OF THE EARTH. 23 



for 3,000 miles in length, and several hundred in 

 width, is one great system of mountains, separated 

 by plains, which, within the tropics, are from 

 twelve to fifteen thousand feet above the sea. 

 Near the equator, Sorato and Illimani tower to 

 elevations of 25,400, and 24,350 feet, according 

 to the measurements of General Pentland. As we 

 proceed northwards towards Mexico, the loftiest 

 peaks are those of Chuquibamba, Gualatiere, 

 Sahama, Cotopaxi, Sierra, Antissana, and others, 

 which vary from 19,000 to 22,000 feet, until we 

 arrive at the table lands of Mexico, which, between 

 latitudes 19 and 24 N. are from six to 8,000 feet 

 above the sea. 



As we advance through the middle latitudes of 

 North America, the rocky mountains average 

 about 10,000 feet. And if we except St. Elias and 

 Mount Hooker, they never exceed 12,000 feet. 

 Nor do the table lands which slope from their 

 base exceed from three to 5,000 : while it is well 

 known that from latitude 60, the elevations dimi- 

 nish on to the polar sea. On the other side of the 

 equator, the highest mountains of Chili are the 

 Acongagua and Descabezado, which, between 

 latitude 32-28 and 35 S. rise to elevations of 

 23,200, and 2 1 , 1 00 feet, from which they all dimi- 

 nish on to Patagonia, and thence to Cape Horn.* 



* It is said that Captain C. Ross has recently discovered in 

 S. lat. 80 a mountain 12,400 feet high. But a few such ex- 

 ceptions are too slight to invalidate the general law. 



