692 Geological Observations made [Dec. 



which alternates with the quartzy-sandstone, often becomes a distinct 

 grey-wacke, consisting of a greyish green base, with numerous angu- 

 lar fragments of clay-slate imbedded. No such appearances could be 

 observed in the slates which alternate with the Mussooree limestone, 

 and this circumstance, coupled with that of superposition, seems to 

 mark the quartzy-sandstone as the newest formation of the two. 



To the north of the Agilwar, we passed over one more ridge of 

 apparently similar composition to the one just described, and then 

 descended into the valley of the Ganges. This valley, where we 

 came upon it, is full a mile broad, and exhibits at different heights, 

 say from 2 to 300 feet above the present level of the stream, flat 

 terraces of gravel, containing boulders, from the size of a pumpkin 

 downwards, perfectly similar to what form the present bed of the 

 river. These appearances continue all the way to its source. In the 

 bed of the river and the precipitous banks that enclose it, we found 

 strata of blue slate, hard and splitting into large plates, uniform in 

 colour and general character, and inclined at a considerable angle to 

 the N. E. — a slate widely different from the soft and parti-coloured 

 varieties, that alternate with the limestone of Mussooree. As we 

 advanced northwards, where our road led us to a considerable height 

 above the river, we met again with, a limestone and slate similar to 

 that at Mussooree, and the overlying quartzy-sandstone, apparently 

 capping all the heights in the neighbourhood. At the end of our 

 second day's march along the course of the river, the quartzy-sand- 

 stone had become the predominant rock, and the slate had nearly 

 disappeared, being only found in the lowest ground opposite Balla- 

 haut. The line of junction of the two was seen only a few feet above 

 the level of the river. Somewhat before this, the slate had partly 

 assumed the character of talc-slate, having a faint glimmering lustre, 

 and a soapy feel. Beyond Ballahaut we continued travelling near 

 the line of junction of the two formations, the slate gradually passing 

 into a perfect talc- slate, and the quartzy-sandstone becoming rather 

 more crystalline than before. Perhaps the name of quartz rock 

 might be more appropriate to it, though it still exhibits in some places 

 traces of round grains agglutinated together. About Batwaree, two 

 marches in advance of Ballahaut, the quartzy-sandstone ceases on the 

 low ground and the slate contains a mixture of quartzy and felspar, 

 forming a talcose gneiss, with hornblende occasionally intermixed. 

 Traces of the quartzy-sandstone yet remain upon the cliffs above for 

 some miles farther to the north, where a gradual passage of it may 

 be observed into the talcose gneiss. We found this talcose gneiss for 

 two inarches further to the north, containing, however, at times a 



