216 REPORT~1869. 



be imperceptible, yet it clearly sliows that there is no danf^er to any permanent 

 work by a general depression of the beds of these rivers going on, as some 

 suppose, because an}^ scooping out of the bed is only local, and can be met by local 

 remedies. 



Borings in the beds of torrents which drain the southern slopes of the hills, and 

 not the interior, and which meander over the plains rather than intersect them, 

 give very different residts to what are found in the ^"alleys of the large rivers, as 

 alternate strata of clay, sand, and kunkur are found. 



It is necessary to know the rainfall at various points to xmderstand certain 

 natural features, and the changes now going on. In the Gangetic valley the rain- 

 fall is considerable, being, on an average, nearly 



20 inches a year at Delhi, 

 30 „ „ 3Ieerut, 



40 „ „ Eoorkie. 



The level of the Bhangir here being so very much above that of the Khadir, a 

 gradual wearing down of the Bhangir is going on ; thus the high level plains between 

 the Ganges and the Jumna, commonly called " the Doab,"' is cut up by several large 

 streams. "With such a rainfall a,s there is all over tlie Doab, it is natural to suppose 

 that there must be some line marking out the catchment basins of each stream, and 

 that this line, by its being least exposed to the action of running water, remains the 

 highest, and is neither more nor less than the " backbone of the country," not 

 caused by any upheaval, but simply that it is worn down less than any other por- 

 tion of the plains. It is along this ridge or ridges that irrigation canals should be 

 led ; but as the plains are so level, the general direction of these ridges is difficult 

 to determine. This at once explains why so many cross sections of the countiT 

 have to be taken to discover the best line for an irrigation canal and its liranches, 

 which are iiOt necessary with a road or a railway where dislance becomes so im- 

 portant an element. 



The author would now make a few remarlis on the valley of the Indus, that is, 

 the plains which form the " Doabs "' of the Punjab, which are similar, geologically, 

 to those of the Gangetic valley, the only difference being that they have not any 

 deep rivers intersecting the plains, nor ridges similar to what ai-e found in the North- 

 western Provinces. 



Take, for example, the Richna Doab, the high level plains between the Ravee 

 and the Chanab I'ivers, which is 50 miles broad near Lahore, where the Bhangir is 

 only about 10 feet above the Khadir of the Ravee ; and on the Chanab side at 

 Wuzeerabad the difference of level is only 17 feet, so that iu a lateral direction 

 there can be very little fall. 



Again, the rainfall is very little compared with what there is in the valley of 

 the Ganges, as approximately it is at Jhuug 4 inches yearly, or i of the fall at 

 Delhi. 



Cheeniot, 8" i Meerut, 



Scalkote, 30" | Roorkie, 



and these points are respectively about equidistant from the hills. The fact is that 

 the land nhsorbs all the rain which falls, so that at fifty miles below the hills every 

 A-estige of drainage-lines disappears. Not that no drainage passes over this line, 

 for it is on tliis parallel that the Lahore and Peshawur road runs ; and 13,470 

 running feet of gaps, in addition to 37 bridges and cuh-erts of various sizes, are left 

 iu this embankment to pass off the cross drainage which comes down from the 

 neighljouiiug country above, where the rain is more plentiful ; yet with all this 

 waterway, in a distance altogether of 50 miles (including the valley of the Ravee ), 

 in July ]SUt; ^' the Jlood topped tltc road for over 8 miles in lenf/th, and made very 

 extensive breaches, scui/rinr/ old the embankment below the level of the coiintnj.'^ 



It appears to the author that in such a case it would perhaps have been better 

 cither to divert the drainage higher up, or to have had no road whatever raised, hut 

 to have allmved the food to pass ijiiieflj/ (ff over the road. The effect in this case, by 

 increasing the velocity at certain points, has been, for the comparatively y;«;-e water 

 which had harmlessly flowed through fields of cultivation, to sweep away scleral 



