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PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 25, 



a country presents, and the very short period that I was able to de- 

 vote to its examination, it will at once be apparent that all I can have 

 to offer is a mere sketch of its more striking geological features, and 

 this I shall endeavour to give as briefly as possible. 



It is right, however, that I should first mention, that a consider- 

 able quantity of the geological information embodied in this paper and 

 my map is derived from the observations of my brother, Mr. John 

 Strachey, of the Bengal Civil Service, who has resided for several 

 years in this part of the mountains ; further, that my own investiga- 

 tions were made during the years 1848 and 1849, while I was em- 

 ployed by the Indian Government in scientific researches of a miscel- 

 laneous nature in the same districts. I am bound to add, that it is 

 altogether to Mr. Thomason, the present Lieut. -Governor of the 

 north-western provinces of Bengal, that I am indebted for my em- 

 ployment in this manner. 



Along the whole of the southern face of the Himalaya, from the 

 debouche of the Indus to that of the Brahmapootra, extends a vast 

 unbroken plain, which is prolonged southward to the Bay of Bengal, 

 near Calcutta, on the one hand, while on the other it follows the In- 

 dus through the Punjab and Scinde to the Arabian Sea, covering in 

 all an area of nearly 500,000 square miles. The highest portion of 

 this^plain is that between the rivers Sutluj and Jumna (see Map), and 

 its elevation along the foot of the mountains is here probably about 

 1200 feet above the sea. On either side of this the drainage of the 

 country flows in opposite directions, falling, as the case may be, either 

 into the Ganges or the Indus, while the level of the surface, as might 

 be supposed, gradually declines as we approach the sea. 



That all of this is a sea-deposit there can be little doubt, although 

 the direct proof, by the discovery of marine shells, is still wanting. 

 Strong grounds for such a belief are, however, afforded by the ex- 

 treme evenness of the surface and regularity of its slope, as well 

 as by the nature of the soil, which everywhere, excepting in the 

 immediate vicinity of the mountains, is a deposit of the most finely- 

 comminuted matter ; so that it is really no exaggeration to say 

 that one might go from the Bay of Bengal, up the Ganges into the 

 Punjab, and thence return to the sea by the Indus, passing over up- 

 wards of 2000 miles of ground, without seeing a pebble however small. 

 The saltness of the wells in the desert tract which extends along the 

 Indus to within fifty miles of the foot of the mountains seems also to 

 point to the same conclusion. Marine deposits, when raised from 

 below the surface of the ocean so as to form dry land, must of neces- 

 sity contain a considerable quantity of the salts found in sea-water ; 

 and when, as is here the case, there are no rivers and no rain, by 

 means of which they may be dissolved and washed out, we may natu- 

 rally expect to find the water of wells in such strata to be salt. 



Close along the foot of the mountains we find the soil to be every- 

 where composed of deposits of boulders and gravel, which become 

 rapidly less abundant as we advance into the plains, and are, I be- 

 lieve, quite lost sight of within a distance of thirty miles from the 

 outer hills. 



