Records of the Geological Survey of India. 
[VOT,. VII. 
82 
exposed beds dip southward, those on the reverse of the anticlinal having been washed away 
by the Artush river up to the longitudinal axis, and thus exposing almost vertical faces. 
These remarkably homogeneous, clayey and sandy beds may appropriately be called Artush 
beds, and although I could nowhere find a trace of a fossil in them, it seems to me very pro- 
bablo that they are of marine origin and of neogcue age. 
The southern slopes of the ridge are on their basal half entirely covered with gravel, 
which in places even extends to the top, assuming here a thickness of from 10 to 15 feet. 
Locally the gravel beds are sepewated from the main range by a shallow dopi'ession, forming 
a low ridge which runs along the base of the higher one, and from which it is, even in the 
distance, clearly discernible by its dark tint. The pebbles in the gravel are mostly of small 
size and well river-worn; they are derived to a very large extent from grey or greenish 
sandstones and shales, black or white limestone, more rarely of trap, basalt, and of gneiss. 
With the exception of the last-named rock, all the others had been met with in situ in the 
upper Toyan valley. The pieces of gneiss belong to a group of metamorpbic rock which is 
usually called Protogine. It is mainly composed of quartz and white or reddish orthoclase, 
with a comparatively small proportion of a green chloritic substance. The white felspar 
variety generally contains as an accessory mineral schorl, in short, rather thick, crystals. 
I shall subsequently allude to the probable source from which the protogine pebbles might 
have been derived. 
From Artush wo marched, as already stated, northwards, up the Toyan river, and for 
the next 22 miles one was surprised to find nothing but the same Artush—and gravel—• 
deposits, the former constantly dipping at a high angle to north by west, and the latter rest¬ 
ing on them in slightly inclined or horizontal strata; while among the recent river deposits 
in the bed of the valley itself the order of things appeared reversed. The gravels, having 
first yielded to denudation, were hero underlying the clays derived from the Artush beds, 
thus preparing an arable ground for the agriculturist, whenever a favorable opportunity 
offered itself. A few miles south of Clningterok the laminated Artush beds entirely dis¬ 
appeared under the gravel, which from its greater consistency assumed here the form of a 
rather tough, coarse conglomerate. In the bend of the river the latter have a thickness of 
fully 200 feet, and are eroded by lateral rivulets into remarkably regular Gothic pillars 
and turrets. It is rare to meet with a more perfect imitation of nature by human art. 
The general surface of the gi'avel deposits is comparatively low, from 400 to 500 feet above 
tho level of the river, and much denuded and intersected by minor streams and old water¬ 
courses. 
At a couple of miles north of Chungtcrek the Koktan range begins with rather abrupt 
limestone cliffs, rising to about 3,000 feet above the level of the Toyan. Nearly in the mid¬ 
dle of it are situated tho forts Murzaterek and Chakmdk, some ten miles distant from each 
other. Tho southern portion of this range consists at its base of undulating layers of 
greenish or purplish shales, overlain by dark coloured, mostly black, limestone in thick and 
thin strata, the latter bemg generally earthy. Tho limestone occupies all tho higher elevations, 
and, as is generally the case, greatly adds to tho ruggedness of tho mountains. About five 
miles north of Chungtcrek, I found in a thick bod of limestone an abundance of Megalodus 
triqueter, a large Pinna, a Spiriferina of the typo of S. Stracheyi, blocks full of Litho- 
dendron corals, and numerous sections of various small Gastropods. Thinner layers of the 
same limestone were full of fragments of crinoid stems, and of a branching Ccriopora, the 
rock itself bearing a strong resemblance to the typical St. Cassian beds. In this place the 
shales, underlying the limestone, were partly interstratified with it, in layers of from 5 to 
10 feet; and from this fact it seems to me probable that they also arc of triassic age, re¬ 
presenting a lower series of the same formation. 
