ON GEOGRAPHY. 439 



" bourhood of the western coast is in general the most elevated ; in North 

 America the Blue mountains, or Stony mountains, are the most consi- 

 derable ; and the mountains of Mexico join the Andes or Cordeliers, which 

 are continued along the whole of the west coast of South America. 



There are several points in both hemispheres from which we may 

 observe rivers separating to run to different seas ; such are Swisserland, 

 Bjelosero, Tartary, Little Tibet, Nigritia or Guinea, and Quito. The 

 highest mountains are Chimboracao and some others of the Cordeliers in 

 Peru, or perhaps Descabesado in Chili, Mont Blanc, and the Peak of Tene- 

 riffe. Chimbora9ao is about 7000 yards, or nearly 4 miles, above the level 

 of the sea ; Mont Blanc 5000, or nearly 3 miles ; the Peak of Teneriffe 

 about 4000, or 2 miles and a quarter ; Ophir, in Sumatra, is said to be 

 5 or 6 hundred feet higher. It has, however, been asserted that some of 

 the snowy mountains, to the north of Bengal, are higher than any of those 

 of South America. The plains of Quito, in Peru, are so much elevated, 

 that the barometer stands at the height of 15 inches only, and the air is 

 reduced to half its usual density. But none of these heights is equal to 

 a thousandth part of the earth's semidiameter, and the greatest of them 

 might be represented on a six inch globe by a single additional thickness 

 of the paper with which it is covered. Mount Sinai in Japan, Mount 

 Caucasus, Etna, the Southern Pyrenees, St. George among the Azores, 

 Mount Adam in Ceylon, Atlas, Olympus, and Taurus are also high 

 mountains : and there are some very considerable elevations in the island 

 Owhyhee. Ben Nevis, in Scotland, is the loftiest of the British hills, but 

 its height is considerably less than a mile. (Plate XXXVIII. Fig. 519.) 



The most elevated mountains, excepting the summits of volcanos, con- 

 sist of rocks, more or less mixed, without regular order, and commonly of 

 granite or porphyry. These are called primary mountains; they run 

 generally from east to west in the old world, and from north to south in 

 the new ; and many of them are observed to be of easier ascent on the east 

 than on the west side. The secondary mountains accompany them in the 

 same direction, they consist of strata, mostly calcarious and argillaceous, 

 that is, of the nature of limestone and clay, with a few animal and vege- 

 table remains, in an obscure form, together with salt, coals, and sulphur. 

 The tertiary mountains are still smaller ; and in these, animal and vegetable 

 remains are very abundant; they consist chiefly of limestone, marble, 

 alabaster, building stone, mill stone, and chalk, with beds of flint. Where 

 the secondary and tertiary mountains are intersected by vallies, the oppo- 

 site strata often correspond at equal heights, as if the vallies had been cut 

 or washed from between them, but sometimes the mountains have their 

 strata disposed as if they had been elevated by an internal force, and their 

 summits had afterwards crumbled away, the strata which are lowest in the 

 plains being highest in the mountains. The strata of these mountains are 

 often intermixed with veins of metal, running in all possible directions, 

 and occupying vacuities which appear to be of somewhat later date than 

 the original formation of the mountains. The volcanic mountains inter- 

 rupt those of every other description without any regularity, as if their 

 origin were totally independent of that of all the rest. 



