VALLEYS AND GBEAT LEVELS OP THE EARTH. 217 



CHAPTER III. 



VALLEYS AXD GREAT LEVELS OF THE EATITH. 



T lias been observed, that the ridge line of 

 a chain of mountains is marked with great 

 irregularities, numerpus breaks and de 

 pressions occurring. Though the base 

 of these depressions is at a high elevation 

 above the general superficies, yet when in 

 ternally surveyed they have all the appear 

 ance of being sunk far below it. The 

 traveller slowly wending his way through 

 them, shut out from any extensive observa 

 tion of the country, and seeing on each 

 hand eminences towering far aloft, might 

 imagine himself at an immense depth be 

 neath the surface land of the globe. They 

 are mountain chasms, through which com 

 munication is maintained between opposite 

 sides of the ridge they intersect, and are 

 called Cols in the Alps, Ports in the Pyrenees, 

 Gaps in the United States, and in general, gates, or passes. They abound with scenes of 

 striking grandeur overhanging rocks, xindefended precipices, patches of wood, and 

 cascades of water, rendered the more impressive by the seclusion of their sites. Some 

 of the present passes across the Alps have been frequented from a very early period, 

 but many natural obstacles have in modern times been removed by the art and labour of 

 man, and the difficult mule paths of a former age been converted into carriage roads. 

 The Carthaginians are supposed to have entered Italy under Hannibal by the pass of the 

 Great St. Bernard ; at least the weight of evidence is in favour of this route, which was 

 made practicable for cars by order of Augustus, and along this course Pepin certainly 

 led his army to attack the Lombards. "It is natural," says Mr. Inglis, "to compare 

 one mountain pass with another ; and after having for the first time crossed any celebrated 

 mountain, one naturally calls to mind the journeys which one may have made across other 

 mountains, and the comparative interest with which such journeys have been attended. 

 I need scarcely say, that there are certain features common to all mountain passes ; that 

 there is sublimity in elevation ; that mountain clefts are filled by rivulets, which swell as they 

 descend ; that plants of less or more interest attract the eye ; that from certain heights, 

 extensive prospects of the country below are laid open ; and that the phenomena of clouds, 

 rain, and rainbows, and the effects of lights and shadows are common to all great elevations. 

 But notwithstanding these features of common resemblance, mountains and their passes 

 widely differ in interest, and consequently in the features by which nature has distinguished 

 them. These differences, supposing the mountains to be equal in height, arise from the 

 diversity in conformation, and the variety in their geological character. When we talk 

 of one mountain pass being finer than another, we mean that the views it affords are more 



