J 841.] CapL Button's Geological Report 207 



the conviction, that nothing but the former presence of deep waters 

 could account for the phenomena here so plainly exposed to view. 



In his conjectures on this head, that enterprising and unwearying 

 traveller was undoubtedly correct. 



In the bed of the Lee, where it is crossed by a wooden sangho, a thick 

 bed of white quartz rock is seen dipping to the S.W., and as we mount 

 the hill in the direction of Chungo, beds of boulders, and disjointed masses 

 of granite, gneiss, and mica slates hurled from above, are passed over, now in 

 many places overlying the secondary shales. 



At the village of Chungo, which is the last on the left bank of the Lee, 

 under the government of Bussaher, the most decided indications of the 

 former presence of a deep lake again occur. To the eastward of the 

 level patch on which the village and its cultivation stands, rise three lofty 

 and rugged mountains, whose shattered sides present sections of the same 

 strata as those noticed at Leeo : namely, deep beds of dark gneiss and 

 mica slates intersected by granitic and quartz veins of various thickness ; 

 these strata dip down towards the west, and as they approach the village, 

 are lost beneath the vast accumulations of alluvial soils, which here, as at 

 Leeo, mark the former presence of deep and tranquil waters. 



To the southward these deposits consist almost entirely of thick beds 

 of clays, sands, and boulders of every size, rising high above the level of 

 the village; while to the NNE. are again presented the same alluvial 

 deposits of a greater thickness, and accompanied in addition by a deep 

 and extensive bed of a pure white and friable gypsum. This bed is per- 

 haps a most valuable discovery in a geological point of view, as tending 

 to show the nature of the waters from which it was precipitated. This thick 

 gypseous bed is overlaid by the sands, clays, and boulders, which have 

 already been noticed. At the fort of Skialkur, on the opposite or right bank 

 of the river, about 3£ miles from the village of Chungo, this gypsum is like- 

 wise seen overlying the transition series of alternating shales and sandstones. 



These deposits are now at the height of 2,000 to 2,500 feet above the 

 present level of the river's course, or at an elevation of 12,000 to 12,500 

 feet above the level of the sea. 



The three mountain peaks of gneiss, which rise up to the eastward of 

 Chungo, are divided from each other by narrow glens, through which 

 streams flow down to join the sea, between which and the base of these 

 mountains, the whole alluvial deposits have been swept away, and the pre- 

 sent cultivated plain of Chungo is therefore situated far below the surround- 

 ing alluvium, which rises like walls on either side of it. 



As we proceed from Chungo towards Spiti, the road lies at first over the 

 alluvial accumulations above-mentioned, for two or three miles, when from 



2 c 



