FAST 1.] 
Sloliczha : Structure of the hill ranges. 
13 
Know, the greatest obstacle a geologist can meet on his survey. While on onr journey the 
thermometer very rarely rose during the day above the freezing point, and hammer opera¬ 
tions were not easily canned out. At night the thermometer sank as a rule to zero, or even 
to 8° below zero in onr tents, and to 2C° below zero in the open air. Adding to this the 
natural difficulties of the ground we had to pass through, it was occasionally not an easy 
matter to keep the health up to the required standard of working power. 
Near Leh, and for a few miles east and west of it, the Indus flows on the boundary 
between crystalline rocks on the north and eocene rocks on the south. The latter consist 
chiefly of grey and reddish sandstones and shales, and more or less coarse conglomerates, 
containing an occasional •nummulite and casts of pelecypods. These tertiary rocks extend 
from eastward south of the Pangkong lake, following the Indus either along one or both 
banks of the river, as far west as Kargil, where they terminate with a kind of brackish and 
fresh-water deposit, containing melanim. 
Nearly the entire ridge north of the Indus, separating this river from the Shayok, and 
continuing in a south-easterly direction to the mouth of the Hanle river (and crossing here 
the Indus, extending to my knowledge as far as Demehock), consists of syenitic gneiss, an 
extremely variable rock as regards its mineralogical composition. The typical rock is a 
moderately fine-grained syenite, crossed by veins which are somewhat richer in hornblende, 
while other portions contain a large quantity of schorl. Both about Leh and further 
eastward, extensive beds of dark, almost black, fine-grained syenite occur in the other 
rock. The felspar often almost entirely disappears from this fine-grained variety, and 
quartz remains very sparingly disseminated, so that gradually the rock passes into a korn- 
blendic schist ; and when schorl replaces hornblende, the same rock changes into layers 
which are almost entirely composed of needles of schorl. Again, the syenite loses in places 
all its hornblende, the crystals of felspar increase in size, biotite (or sometimes chlorite) 
becomes more or less abundant, and with the addition of quartz we have before us a typical 
gneiss (or protogine gneiss) without being able to draw a boundary between it and typical 
syenite. However, the gneissic portions, many of which appear to lie regularly bedded, are 
decidedly subordinate to the syenitic ones. As already mentioned, the rock often has a 
porphyritic structure, and the felspar becomes pink instead of white, as, for instance, on the 
top of the Kardung pass and on the southern slope of the Chang-la, where large fragments 
are often met without the slightest trace of hornblende. To the north of the last men¬ 
tioned pass the syenitic gneiss gradually passes into thick beds of syenite-schist, and this 
again into chloride schist, by the hornblende becoming replaced by chlorite, while the other 
mineral constituents are gradually almost entirely suppressed. The syenitic and chloride 
beds alternate with quartzose schists of great thickness. This schistose series of rocks 
continues from north of the Chang-la to the western end of the Pangkong lake, and 
northwards to the Lunker-la, generally called the Marsemik pass. On the western route 
Dr. Bellew met similar rocks north of the Kardung pass at the village Kardung, and 
traced them northwards across the Shayok, up the Nubra valley to near the foot of the 
Sussir pass. 
Intimately connected with the metamorphie schistose series just noticed, ls a greenish 
chloritic, partly thin-bedded, partly more massive rock, which very closely resembles a similar 
rock found about Srinaggar. Only in this case certain layers, or portions of it, become often 
distinctly or even coarsely crystalline, sometimes containing bronzite sparingly disseminated, 
and thus passing into diallage. This chloritic rock forms the greater part of the left side 
of the Ckangchenmo valley, and also occurs south of the Sussir pass. I think we have to 
look upon this whole series of schistose and chloritic rocks as the representatives of the 
Silurian formation. 
After crossing the Ckangchenmo valley to Gogra, we met with a different set of rocks. 
They are dark, often quite black, shales alternating with sandstones. Many beds of the 
