GEOLOGY. 
27 
f' . a °^ rci ^ 01 white sandstone, thus addin: 
to the remarkable contrast of the scene. In 
pern 'r an( ^ ^ le right, stretched in a semicircle a regular old Somma ; the almost 
catioiTo^tl T U l ^ S risi ^ a h°iit 1,500 feet above the river, and clearly exposing the stratifi- 
es U On ° ^ aSa ^ c ® ows > which were successively dipping to north-east, east, and south- 
were ' ' -1 n ° UI as we ^ as in an almost due western direction, portions of a similar Somma 
0 f Us Vl8 ' 0 a ^ )ove the sedimentary rocks, all dipping in the opposite way from those ahead 
filler! vi ll 'i Ct ne ^ as hi reality entirely disappeared by subsidence, and the cavity was 
wi it e rubbish of the neighbouring rocks. 
hills briber north we crossed a comparatively low country, studded with small rounded 
and 13 ( m tercepted by short ridges, with easy slopes ; the average height was between 12,000 
j£ u j . J 5 feet. This undulating high plateau proved to he one of the head-quarters of the 
thi K * S ^ are ^ n ^> chiefly on account of the very rich grass vegetation which exists here. 
lhn.e t ^ 1 ^ ( ' ^aracter °i the soil fully accounts. The entire ground was shown to consist of 
tus ' -T' » l av< 'l ail d pebbles of rather easily decomposing rocks, mixed with the ashes and detri- 
fias' H • K Cn ' ^ drived from the proximity of the volcanic eruption. Only rarely was an isolated 
ic dyke seen, or the tertiary sandstone cropping out from under the more recent deposits. 
c ^* e wing the country from an elevated position near our camp at Turgat-bela, the 
cask ° mera ^ e anf l gravel beds, well clad with grass vegetation, were seen to stretch far away 
Were an< ^ * n a n °rih-easterly direction across the Turgatpass; while on the south they 
j e °ttnded by a continuation of the somewhat higher basaltic hills. Towards the west 
ri Se * a ? e< ^ fhem for about 7 miles, across a low pass at which a tributary of the Toyanda 
the S ^ * W ° l nanc hes ; while on the other side two similar streams flow west by south to join 
r est laver - r f° the north the proximity of a rather precipitously rising range shut the 
he r °+ .^ 1C W01 ’ld out of view. Eor this ridge the name Terak-tagh of Humboldt’s map may 
tester aine ^ ’ avera g e height ranges between about 16,000 and 17,000 feet. In its 
cone*] a ex ^ ens f°tt it runs almost due east and west, composed at base of a tough limestone 
a su b c 0m . rate 5 r ° un S er tertiary origin, followed by white dolomitic limestones, and then by 
si ".tt 8 C< 7 0 * °f slaty and dark limestone rocks, the former occasionally showing distinct 
hhe pi ° . me tattiorphism, and changing into schist. All the beds are nearly vertical or very 
■^erth in< ^' nec ^ dipping to north by west, the older apparently resting on the younger, 
and (•' °- ^ ur & a t-i)ela the range makes a sudden bend in an almost northerly direction, 
Py ail tittues to the Chadyr-kul, where it forms the southern boundary of the lake plateau. 
a ttd --fi t * me f^ 1(; white dolomitic, and afterwards the slaty beds, have entirely disappeared, 
t] le them the height has also diminished. A comparatively low and narrow branch of 
which we visited consists here entirely of dark limestone, which in single frag- 
it do !■ 1S n ° ^ distinguishable from the trias limestone of the Koktan mountains, but here 
dire r U °^ C0:a tain any fossils. The ridge itself, after a short stretch in a north-east by north 
n ’ gradually disappears under the much newer conglomeratic beds. 
pcaks^ Cr ° SS ^’ e Chadyr-kul plain the true Thian Shan range was visible, a regular forest of 
tints 1 SCemin gly °f moderate and tolerably uniform elevation. The rocks all exhibited dark 
°f ^ ^ niost of them, as well as the hills to the west of the Chadyr-kul, near the sources 
* P a > were clad in snow. The lake itself was frozen, and the surrounding plain covered 
a white sheet of saline efflorescence. 
P r ececT ? 8 ^ e ^ 1 °f the geological history of the hill ranges traversed.— In order that the 
& remarks may he more easily understood, I add a few words regarding the changes 
