Chap. II] the Himalayan series. 35 



the spur to the north of the synclinal, — a fact that increases the probability 



of their being the representatives of the Krol sandstones. In these 



schistose quartzites is found, very well developed, a structure that has, I 



think, been described by the name bacillary, con- 

 Bacillaiy structure. 



sisting of very straight ribs and grooves, both being 



scored with minor ribs and grooves. This structure occurs in the plane 



of the bedding of the rock, and generally transverse to the present dip ; 



but I failed to trace any constant relation between the two. 



I have yet to mention the highest rocks that occur about Simla. 



To the west of the toll-bar gap there must be a fault along the 



synclinal axis, with a considerable downthrow to the south-west, and 



accompanied by a general subsidence of the rocks to the north-west 



of Tara Devi. This line of fracture passes through a portion of the 



Simla ridge at Jatog, and we find there a con- 

 Fault south of Jatog. 



siderable thickness of the strata that overlie the 

 quartzites. The section is best seen on the south-westerly spur from 

 Jatog hill. The quartzites occupy the lower extension of the spur, 

 corresponding to the Sairi ridge at Jatea Devi, and they have the 

 same low dip to north-north-east ; over them on the ascent there is a 

 considerable thickness of dark blue limestone, schistose and carbonaceous, 

 or perhaps more accurately, graphitic. Above these there come more 

 schists, highly altered, almost gneissose, and then again strong-bedded, 

 hard, blue limestone, with much irregular chert. Over this there are 

 some garnetiferous mica-schists, but being at the summit, and in the 

 very line of disturbance, their position may be doubtful. On the whole, 

 these uppermost beds of the Jatog section correspond well with those 

 which we have already noticed in attempting to identify the whole 

 series of these rocks about Simla with those of the Krol section. I 

 believe we have here the Krol group in a more altered state. 



All these Simla rocks, from the Blini group up, present the same 

 difficulty, — that of their highly metamorphic condition as compared with 



