202 



PHYSICAL GEOGRAPHY. 



The length of the principal chains has been computed as follows : 



Miles. 



The Andes - - 4500 



Mexican and Stony Mountains ' - 7000 

 Whole American chain - 11,500 



Altaian mountains - v. ; 5000 



Mountains of the moon, supposed - 2000 

 Ural chain - * . 1500 



Mount Atlas - - /- 1500 



Dofrafeld - 



Olonetz mountains - . 



Allegany 



The Alps and the Apennines 



Carpathian mountains 



Green mountains 



The Pyrenees 



Miles. 

 10OO 



-' 1000 



.'-' 900 



600 to 700 



500 



350 



200 



The contour of mountains exhibits almost every kind of variety, .and their aspect 

 changes as an observer extends his distance from them, lesser irregularities being lost in 

 the general outline, and different colours becoming merged in a uniform shade. The 

 appearance of solitary individual objects is generally conical; but others are circular, 

 elliptical, or saddle-backed. The Table Mountain at the Cape of Good Hope has the shape 

 of a gigantic altar. In the case of a number of contiguous mountains, their summits 

 are often needle-shaped, or like the domes of Roman architecture. In many in- 

 stances the entire mass resembles a vast wall, with battlements and towers, after the 

 manner of an ancient fortress, and sometimes mountains appear piled upon each other, 

 forming a succession of gigantic terraces. One of the most extraordinary mountains in 

 its configuration is in the Mauritius, a volcanic region, and bears the name of Peter 



Botte. The name is derived from an un- 

 fortunate adventurer, who, according to 

 tradition, after reaching the summit, pe- 

 rished in the descent. An enormous 

 mass, of a globular shape, forms the head 

 of the mountain. It rests upon a pe- 

 destal of rock, of a conical form, upwards 

 of three hundred feet high, and overhangs 

 it by several feet. At the bottom of the 



Peter Botte Mountain. 



j&destal, a narrow strip of land runs out, 

 ^ about six feet broad, and twenty yards 

 long, on two sides of which a precipice 

 goes down direct fifteen hundred feet to 

 the plain, the other side being a very 

 steep wooded gorge. The view from the 

 narrow ledge, as may be imagined, is 

 tremendous in the extreme, and the still 

 ascending conical rock with its overhang- 

 ing head seems secure enough from the 

 intrusion of man. The Peter Botte has been usually considered inaccessible. Many 

 endeavours to reach the top have been made without success, but the enterprise was 

 at length effected in the year 1832, by the skill and daring of a party of British officers, 

 who, after surmounting the uppermost block, spent the night immediately under it. 



The internal structure of elevations, as well as their external shape, displays great 

 diversities. In fact, their outward character has been determined in a great degree by 

 the substances of which they are composed. The granite mountains are the loftiest upon 

 the surface of the globe, and present the most rugged and broken aspect, with very pre- 

 cipitous sides. Those of gneiss and mica slate are not so wild and irregular, nor are their 

 declivities so steep ; and those composed of secondary formations sandstone, limestone, 

 and greywacke are of inferior elevation compared with the former, and the declivities 



