Page:Encyclopædia Britannica, Ninth Edition, v. 11.djvu/864

824 HIMALAYA that flow from the mountains, and under the full influence of the periodical rains, and it comprises the best cultivated, the richest, the most populous, and most civilized districts of India. ie The snowy peaks of the Himalaya are, under favourable irai. conditions, visible from the plains at a distance of about 200 miles. It is not, however, till the traveller is within 30 or 40 miles of the foot of the mountains that the outlines of the great peaks become well defined and their grandeur appreciable. At about the same distance, too, the lower ranges begin for the first time to attract attention. At about 20 or 25 miles from the outer hills the cultivation of the plain commonly becomes less complete, and the villages more sparse ; an open grassy tract is entered, often traversed by shallow, sluggish streams, along which are formed morasses, or fringes of gigantic reeds and grasses, frequently occupying very large areas. This tract is known as the " Tarai," or " Tariyani." Where most strongly developed it has a width of 10 or 15 miles, but its exist ence is manifestly greatly dependent on the local conditions of drainage and of rainfall, and to the west of the point where the Gauges leaves the mountains the Tarai is not former!. It has besn erroneously described as a depression along the foot of the mountains, but there is no foundation for such a view, and the causes that lead to the formation are not far to seek. ie To explain these it is necessary to take a further step tabar. towards the mountains. Just as the Tarai somewhat suddenly appears along a certain definite line, so it as suddenly ceases, and is replaced by a band of forest of about equal breadth, known as the "Bhabar." This tract is almost waterless, and the soil is seen to be chiefly sand or shingla, more or less filled with boulders. The streams that issue from the outer hills on entering the Bhabar are for the most part rapidly absorbed, and finally disappear in their sandy or shingle beds, the water they pour into the soil being again discharged along the outer and lower border of the tract, and collecting once more in the streams which characterize the Tarai. ow The Bhabar and Tarai slope continuously from the foot naed. O f t^ mountains to the cultivated plain. The inclination is so uniform as to be hardly perceptible, but becomes gradually less as the distance from the mountains becomes greater. Observation leads us to suppose that the upper part of this talus, lying along the foot of the outer hills, is composed of coarser matter, and the lower part, which comes into view at a greater distance, of a finer and less permeable silt ; and that, the latter having a smaller in clination and extending further than the former, the water absorbed by the upper beds will naturally be brought to the surface at their termination, where the finer materials forming clayey strata make their appearance. That the swampy Tarai is not developed in the western part of the range is doubtless due to the smaller rainfall in that region ; while its more marked occurrence to the east of the Ganges at irregular intervals arises from the local peculiarities of the surface drainage, which at some places is carried off directly into the larger rivers without check, and in others is forced to follow a line nearly parallel to that of the mountains for considerable distances, through a tract from which there is no free escape for the water ; and which, thus becoming water-logged and covered with a rank development of vegetation, acquires its peculiarities, among which has to be reckoned a climate in which fevers of a deadly character are frequently induced, rendering its permanent occupation and cultivation difficult or im possible. The transition from the plains to the mountains is sudden and well-defined along a line that is almost continuous. The ranges to which geologists have given the, name of "Siwalik," and " sub Himalayan," rise abruptly, and with- Siwdlil out any intermediate undulating ground from the apparently or sub- level surface of the plain. These hills, which from recent IIinia ~ geological investigation we learn to be formed of deposits aja of various periods of the Tertiary epoch, attain elevations from a few hundred to 3000 or 4000 feet. The dip of the strata composing them is usually at a low angle towards the mass of the mountains, so that they present a steep face to the plains, while a comparatively easy declivity slopes inwards, and frequently, by meeting a corresponding but longer and more gradual talus descending from the foot of the internal line of mountains, forms a shallow, narrow valley which runs generally parallel to the outer range. These valleys, which are very characteristic of the outer The border of the mountains, have by some writers been Dij" s < erroneously confounded with the Tarai. They are termed ^ Iaii - " Dun " in the western regions ; in Nepal they are known by the name of "Mari." Their floors consist of deposits of gravel and boulders, having a maximum elevation of about 2000 or 2500 feet above the sea. Their continuity is broken at intervals by low, transverse, watershed lines, from which the drainage is thrown off along their longitu dinal axis, and falls into some of the larger streams which cross them from the inner ranges, though less frequently it finds an independent exit into the plains by a sudden bend to the south through a rupture in the line of outer hills. At intervals these valleys are entirely wanting, and the outer hills which form them elsewhere are undistinguishable from the general mass of mountain within, except through the aid of their geological character. From the considerable elevation of the duns above the plains, down to the level of which the streams whijh drain them descend in a very short distance, the unconsolidated strata which form the floors of these valleys are often deeply cut into by the watercourses, and present a surface worn into terraces descending in steps of various heights. These conditions lead to a peculiarity which characterizes large parts of the duns, the almost complete impossibility of getting water from wells, due no doubt to the thorough desiccation of the subsoil. The sub-Himalayan ranges have a well-defined distinct Exteni geographical existence along the greater part of the chain, of ^ sub and their geological continuity is established where no valley , ima is formed between them and the inner ranges, and where they cannot be otherwise distinguished from the general mass of mountains. To the west of the Sutlej river these ranges and the valleys connected with them have an unusual development, the width over which they extend increasing from 10 or 15 miles to as much as 50 miles, with a series of two or three dun-like valleys one within another. West of the river Jhelum, again, the aspect of the outer Himalaya is entirely modified by a small table land, which is formed to the north of the line of elevation known as the Salt range, and extends to the Indus. Its general surface lies at about 1000 feet above the general level of the plain, having a maximum elevation of about 1800 feet, and being remarkable for the extraordinary manner in which it is broken up by ravines, the number, gigantic dimensions, and intricacy of which are alike per plexing and astonishing the extremely dry climate leading to an almost total want of vegetation, and the absence of any such concealment exhibiting a picture of confusion and desolation not often seen. The ranges which lie immediately within the external Outer band of the Siwaliks, or sub-Himalaya, rise abruptly above ranges it to much greater elevations, and constitute the first masses " iai . n which in such a region we can with propriety dignify with the name of mountains. Their ordinary elevation is about

7000 feet, and the highest summits on them reach 8000