1841.] Capt HuttorCs Geological Report. 225 



sands, and pebbles now seen in the lower parts of the valley of the Sutledge, 

 to which allusion has been made in the commencement of this paper. 



Having now, I trust, satisfactorily showed how the theory proposed, and 

 the facts observable, are in accordance, it only remains, before bringing 

 the subject to a close, to take a brief and rapid glance at the geological 

 formations of the lower hills from Kotgurh to the foot of the mountains. 



Taking that station, therefore, again as a starting point, and proceeding 

 towards Simla, we find the formation to consist principally of mica and 

 clay slates, the one constantly fading into the other, and occurring in 

 frequent alternations. — Quartz veins are numerously interspersed in the 

 beds of mica, which is sometimes of a soft and scaly nature, containing but 

 little quartz, — at others hard and compact, exhibiting little trace of the mica. 



The mountain of Huttoo, which rises near Nagkunda to the height of 

 10,656 feet of elevation above the sea, is composed of mica slate and 

 gneiss, while its summit exhibits some rugged peaks of granite jutting 

 upwards through the strata. 



The soils which occur from Kotgurh to Simla, are formed chiefly from 

 the decomposition of the clay and mica slates, with the addition often of a 

 rich vegetable mould. 



Descending from Simla towards Subathoo, the primitive formations 

 again yield to the secondary series, exhibiting dark blue limestones and 

 many alternations of slate clay of different colours ; dull-greenish, yellow- 

 ish, and purple. The latter is also seen as the poste or matrix of a quartz- 

 ose breccia composed of angular fragments of white quartz. 



Around Subathoo the change becomes the most decided, and the strata 

 are there seen in perfection, consisting of the usual thick beds of clays and 

 marles, varied with veins of gypsum, and resting on a red marie, apparently 

 analogous to the red marie of England. The strata are here often upheaved 

 nearly to a verticle position, and thick beds of shell limestone* are found 

 alternating with thinner strata of compact limestones, containing castes of 

 bivalve shells, similar to the " Venus angularis" of the European strata. 

 Large specimens of Ostrce also occur, as well as compact strata, almost 

 entirely composed of small species of the fresh-water genera, Melania and 

 Poludina. 



The presence of these last prove again, beyond a doubt, that fresh water 

 must have occupied eventually the basins in which the marine strata of 

 the secondary series were deposited, and leads to the supposition, that 

 nearly the same causes were instrumental to the formation of that series, 

 as we have just shown to have been conducive to the deposition of the 

 diluvium and alluvium of the Spiti valley. 



* Strata composed almost entirely of shells. 



i 



