Records of the Geological Survey of India. 
[vol. IX. 
marked on my map as a Siwalik-Nahan "boundary—is clearly defined for a much greater 
distance westward than the Nahan-Siwalik break of the Simla region. On the Ravi, as all 
through the Kangra district, the Siwalik conglomerates are in great force along it; but 
west of the river an oblique strike brings in lower beds, which are less distinguishable; still, 
the feature as a structural break is easily followed to near Udampur, where the fault dies out 
in the irregular flexures of the region of the Choti-Tawi. Here one must trust to aboriginal 
characters of the strata in any attempt to separate the lower as well as the upper zones of 
tertiary rocks. 
In examining the extension of the inner belt of tertiaries this year, I hit upon two 
outcrops bearing on this point. Where this zone runs north and south along the left bank of 
the Ravi, under the point of the Dhaoladhar ridge, it is very much compressed, being not 
moie than a quarter to half a mile in width. In this very crushed, probably inverted, 
outciop I found a characteristic sample ot the Ivasaoli plant bed, the only occurrence of it 
known west ot the Satlej. Should the unconformity between the Kasaoli and Mahan 
horizons in the eastern region he confirmed, this observation will extend the separation of the 
zones up to the Ravi; and I shall have been over-cautious in introducing the Nahan strata 
in this position so far to the eastward on my map. 
Where the Ravi leaves its mountain gorge and turns sharply to the south, there is also 
an acute bend in the strike of the bottom tertiary zone, and from here to fshe westward this 
band increases steadily in width, chiefly owing to the gradual retreat of its inner boundary, 
which crosses the high ridge into the Chenab valley north of Chineni. The breadth here at 
fifty miles from the Ravi is over twelve miles. Iu the valley of the Pine over the village of 
Martin, fifteen miles from the Ravi, I got a small outcrop of earthy nummulitic limestone, 
the first identification of the Subathu zone west of the Beas. This case illustrates well the 
difficulty of fixing the bottom division of the tertiary series—the Subathu-Dagsbai boundary, 
if the Sirnuir group maintains its distinctness so far; or the Subathu-Nahan boundary, if 
the Upper Sirmur group merges into the Mahan group, as seems certainly to occur at some 
part between the Ravi and the Jhelam. This nummulitic outcrop on the Pine, in the midst 
of a great section of bright red clays and pale-greenish sandy beds near the south boundary 
of the Sirmur band, is about the highest position in which I have found nummulities; and it 
exhibits again how closely the great supra-nummulitic red deposits are connected with that 
formation in the Plimalayan region. 
T may here note an important observation I made this year regarding the inner boundary 
of this oldest tertiary zone. In the position already noticed along the west base.of the 
Dhaoladhar where the recognisable band of these rocks is so narrow, bemg compressed 
crushed, and apparently inverted, there is no definable boundary between them and the 
contiguous rocks of the mountain which here consist of a broken amorphous mass in a semi- 
metamorphic trappoid condition, red and green vesicular and quasi-amygdaloidal pseudo-trap 
being the prevailing type. The amygdala are not the smooth vesicles pr, duced by elastic 
fluids m a fused rock ; they are of irregular shape, but are quite filled with infiltrated minerals 
There is a magnificent fan oftbed6bvis of this crumbling mass just below Simliu, and now 
deeply cut into on the left bank of tlie Ravi. I could not but conclude that this peculiar rock 
is a metamorphosed condition, through enormous pressure, of the Subathu nummulities. Now 
it exactly resembles the so-called trap of the Pir Panj.il aud Kashmir, the debris of which is 
the most abundant shingle in the torrents from that range, and of the age or origin of which 
there is no definite knowledge. If the observation here recorded can be extended to that 
region, an important step will be made towards understanding its intricate geology. 
As the inner tertiary zone expands to the west of the Ravi, the enormous thickness of 
the supra-nummulitio groups has room to display itself. The cross-gorge of the Choti-Tawi 
is a line of depression, the rocks of the high ridge to the north-west of it havin°- a steady 
south-easterly clip. Strata much higher in the series occur here. There are thick masses of 
