PART 4 .] 
McMahon : The Simla Uimalaijas. 
205 
Jatog; and to pick them up again one has to cross the spur and descend into the gorge oE 
tiie Sunal Biver which runs down from the Combermere Bridge, Simla, over the “ Water- 
Falls” into the Ussan. The Blaini limestone shows first on the west side of this ridge 
under a house called Data, near the hamlet of Darmachi, and thence in a north-westerly 
direction until it cuts across the hed of the Sunal under the village of Kwara. It is here 
seen typically resting directly on the Blaini conglomerate. The outcrop may ho followed 
on the right or west side of the Sunal valley as far as Shail, but a little beyond this it is 
again cut off by the fault above alluded to. Following the line of strike from Shail, one 
comes on highly metamorphie schists of the Infra-Krol series, and all trace of the Blaini 
beds is lost. Lower down in the bed of the Sunal the line of fault may be clearly seen, 
the black carbonaceous Iufra-Krol rocks, being on the left bank, brought into juxtaposition 
with the clear purple and greenish-grey Simla slates, with little disturbance of dip at the 
line of junction. Higher up the line of fault, the Simla slates have suffered violent 
contortion. 
Descending the Sunal into the IJssan Biver the Blaini limestone is again picked up on 
the left bank of the Ussan at Kalog Bag* * * § Between Shail and Balog Bag the intermediate 
rocks belong to Infra-Krol series. From Kalog Bag there are several exposures of the lime¬ 
stone in and adjoining the IJssan until a low southerly dip takes it below the bed of that 
river. Further on, a northerly dip sets in and rapidly becomes very high. The rocks are 
nearly vertical in the narrow gorge of the Ussan just below the junction of the Tandalailf 
stream. The Blaini limestone^, is not exposed here, but the conglomerate is in great force. 
The conglomerate as seen here deserves, I think, especial study, as an acquaintance with it 
may lead to the identification of the rock at other places. There are several beds of it— 
some sparsely, others abundantly conglomeratic. The sub-angular or partially rounded 
blocks of slaty grit are absent, but the white quartz “ eggs” are very abundant. Some¬ 
times conglomerate is very fine-grained, and it probably passes into the Blaini quartzite 
sandstone. This variety of the Blaini conglomerate is at times much flowered over and 
pierced by white quartz-veins, and a person not familiar with the rock might easily he 
led to suppose that its peculiar appearance is wholly due to metamorphie action. A close 
inspection, however, shows that the rock is a true conglomerate; rounded pebbles of dark- 
grey or purple quartzite are sometimes freely scattered amongst the white quartz “eggs,” 
and the former at times contain one or more thin white veins which do not pass into 
matrix, showing clearly that the metamorphism of the contained pebble was effected before 
it was worn down into its present shape and buried in the matrix. 
Following the line of strike which leads at first along the crest, and afterwards 
along the flank of the spur that runs up from the Ussan Biver to the peaks above Kyari 
Ghat,§ the limestone crops out again at Badun. The dip is north-east down into the 
Tundalail, and the limestone is seen twice between Badun and the stream. In the bed of 
the latter there is about 60 feet of it, thin-bedded and nearly vertical. It is hero, by local 
coutortion, jammed into the dark Infra-Krol slates, and partakes of the colour of the latter. 
Following the line of strike from Badun, the limestone is again seen between that 
village and Basna. Near Basna the black Infra-Krol rocks and Simla slates are seen 
together. Following the line of junction of the two rocks, I passed over the crest of 
the ridge and landed at the exposure of the Blaini limestone on the Simla and Kalka 
* A little west of Tharala of the map. 
t This is the stream marked on the map as flowing down from Dhar, where it has its rise near the Kalka and 
Simla road, past Tundul of the map. 
$ In the slates at no great distance, there is a calcareous slaty bed. 
§ Kyari Uhat is a Dak Bungalow on the transverse spur a little to the north of Kura of the map. 
