o30 Dr George Buist on the 



tude of 8500 feet, — and, thirdly, of the low land on the 

 seaboard betwixt the foot of the hills and the shore. 



Without at present taking into account the Sooliman and 

 the Himalaya mountains, India, beyond the limits of the pen- 

 insula northward, exhibits four grand divisions of surface, — 

 1st, The great river deltas of the Indus and Ganges, consist- 

 ing of almost pure alluvium, yearly adding to its mass, and 

 which furnish by far the most fertile portions of the country ; 

 2d, The Doabs, which may be described as the converse of 

 the deltas — the latter being the rich lands which lie around 

 the mouths, the former those which separate the branches 

 of our principal rivers ; both being to a greater or less extent 

 subject to inundations, the Doabs being particularly acces- 

 sible to artificial irrigation ; 3d, The Great Desert, which 

 lies to the eastward of the Indus, and southward of the 

 Sutlej, towards Delhi, and which long formed the defence of 

 the British frontier ; and, lastly, The Terai, or gravel belt, 

 which skirts the base of the mountains, — a tract of compara- 

 tively inconsiderable size, but so singular in point of struc- 

 ture as to be deserving of a separate notice. 



The Terai, or Tauri, is a large gravel belt, filling, to the 

 depth of from 15 to 150 feet, a narrow, basin-shaped hollow, 

 from 5 to 15 miles in breadth, and from 500 to 600 in length, 

 skirting the base of the Himalayas. It is so penetrable to 

 water, that rivers, after traversing it for a short distance, 

 sink down and disappear under its surface, re-appearing 

 again when a fault, dyke, or other obstruction, is met with, 

 once more to disappear when this is passed. The marshes 

 thus formed are so malarious, that the husbandmen by whom 

 portions of the Tarai are tilled hasten away from it as evening 

 approaches, and make their abode high up amongst the hills. 

 The insalubrious character of this singular region, at certain 

 seasons of the year, pervades the vast Saul forests which skirt 

 its margin all along ; they are waterless, rivers sinking be- 

 neath them, and emerging in the Terai ; and Nepaul is girt 

 around by a border at times so dangerous to human life that 

 for months together no one attempts to traverse it. 



River Systems of India. — In India we have two stupen- 



