1857.] Beport on the Progress of the Magnetic Survey. 131 



central crystalline rocks is very limited indeed. Large tracts of 

 country in the Himalayas, south of the water-shed, are occupied by 

 sedimentary marine strata, which contain in several places fossil 

 remains. The slate and limestone mountains about Kashmeer 

 yielded a large number of oolitic fossils many identical with those 

 found in Thibet, the same were met with in Kulu and in the moun- 

 tains near Simla. To the eastward, where as yet no fossils have 

 been discovered, the alteration of the sedimentary strata by intrusive 

 felspathic rocks seems to have been more considerable than at the 

 western end of the chain. To the south of Kashmeer a zone of 

 nummulitic marls and of sandstones of 39 to 50 miles broad bor- 

 ders the Himalaya towards the plains of India. 



16. From the observations now collected, it seems that the 

 ocean in the oolitic period extended from the southward across the 

 country where the Himalayas are now situated as far as Thibet. 

 The ocean of the nummulitic period on the contrary no longer ex- 

 tended so far to the northward. It covered a large part of western 

 Asia, of Scinde and the Punjaub, aud had its border formed by 

 an elevated range of the then already existing Himalaya. 



17. The excavation by the valleys of the eroding power of 

 streams has been carried on to a very great extent — the considerable 

 fall, which rivers like the Indus and Sutlej experience on their 

 course from Thibet down to the low plains of India, has increased 

 their excavating power in a surprising manner. 



In the valley of the Indus near Iscardo, in the valley of Astor 

 near the place where the Indus enters the Himalaya, I on several 

 occasions observed gravel, and sand beds evidently deposited by 

 these rivers, and ancient marks produced by the large streams 

 on the rocks at elevations of 3,000 and 4,000 Eng. feet above the 

 present level of the rivers. We have many proofs independent of 

 each other to show the great depth to which all the valleys of the 

 rivers tributary to the Sutlej and Indus have been excavated. 



18. In the western Kuenluen very large glaciers from 10 to 

 15 miles long exist in several valleys. We mentioned last year 

 that in the Himalayas nearly all glaciers show evident marks of 

 being somewhat smaller at present than they were at some former 



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