MOUNTAIN

(Lat. mons.) In Geography, the term applied surface.to Mountains designate the and principal hills, says elevations Bake well,on are the relative earth's terms with respect to each other, the highest elevations being denominated mountains, and the lower hills. In the vicinity of Mont Blanc and Mont Rosa, which are more than 5000 yards high, the mountains in Cumber land and North Wales would be called hills, though Snowdon rises more than 1100 yards, and Skid daw and Helvellyn more than 1000 above the level of the sea. In England, if hills rise abruptly, and are more than 400 yards above the surrounding country, they are generally called mountains. Sec Geology. Arrangement of Mountains. — Mountains are seldom found insulated or detached: sometimes, though rarely, thoy exist in aggregate groups, branching from a common centre, and not externally connected; but most commonly they are extended in ranges or mountain chains, traversing extensive regions. A single continuous chain is of rare occurrence: in general, a number of chains is a ociated; though there does not. seem to be any predominating form of aggregation or direction, at least with reference to the whole surface of the globe. In some instances there is a principal or central chain, with secondary groups branching off from it; in others, several chains are a ociated, to no one of which the rest can be said to be subordinate; and in others again, as the Cordilleras, a series of chain's succeed each other, all running in one constant direction. It has been surmised that the direction of the principal mountain chains is that of the line of greatest length of the continent'or region to which they belong; but this idea, though rendered plausible by some remarkable instances, can scarcely be said to be borne out by the facts. In a very general view, it may be stated that the predominating direction of the great mountain chain? of the old world is from west to east, while those of Araer ca range from north to south. See Geography. Another generalization, which seems to be liable to fewei exceptions, is, that mountain chains or ranges present the steepest acclivities on the sides nearest the sea. This arrangement is particularly observable on the shores of the Mediterranean: the mountains of Armenia present their precipitous sides to the Euxine, and those of Caucasus and Mozanderan to the Caspian. The western Ghauts face the Indian Ocean; and the whole range of the Cordilleras, with their prolongation to the Arctic. Ocean, presents its escarpments to the great Pacific. On tte hypothesis that the con tinents and mountain ma es have been upheaved by a force acting in the Interior of the earth, these peculiarities of configuration afford scope for curicus.'peculation respecting the prodigious efficacy of the subterranenn agencies through form. which the crust of the earth has a umed its actual Altitude of Mountains.— On taking a general view of the surface of the earth, the elevation of the loftiest mountain chains, enormous as it appears to be, is insignificant iu comparison of the dimensions of the globe. The radius of the earth is nearly 4000 miles; while the height of the high-*.-' [s. 794]