Geography of Eastern Asia. — Hobbs. 75 
a line that continues the Tsiii-ling-scluiii ( Tsin-ling range) line, form a 
densely crowded network, though northward of that line they are spaced 
with wider intervals. Westward from the series of crescents, navigation 
is interfered with or is difficult; only on the Ya-ug sze-kiang (Yang-tze- 
rrver) there lies farther up in the Red Basin of the Ss-tschwan (Sze- 
chaun) still, one other region of better navigation as a consequence of 
regionally less intensive and more intensive erosion. 
3. Commercial geographig. Commerce is conducted in general freely 
and openly to the east of the series of crescents ; except in south- 
eastern Manchuria where the mountains fix its limit. The land-steps, 
in spite of their generally small altitude, present a bar to commerce, 
which, on these land routes, as in the case of ocean routes, have only 
in a few cases been overcome. Maritime east Asia is hence closed 
off from the inland country. This is even in those places the case, 
where, as in Schcn-si (Shen-si) and Mongolia, open lands again follow 
upon the other side with easy conditions of communication. 
4. Climatic. Although all land in east Asia, or as far as Ochotsk 
(Okhotsk), is under the influence of monsoon climate, yet the dividing 
character along the line determined by the step borders is in some 
places recognizable and probably everywhere present. The separation 
is sharp in Stanoz>.'oi (Stanovoi). It is present in the Scya (Zeya) range 
and Olckma ranges and the Khingan as shown by the contrast of the 
park landscape and the deciduous features on the Amur with the Siber- 
ian conifers and the dry steppes of Mongolia. Only in one region west 
from Nonni and Tung-liau-ho (Tung-lia river) do the latter extend 
eastwards over the Khingan. For the stretches lying farther to the south 
it is sufficient to point out the contrast between the great plain which ex- 
tends frcm Pekin to Hivai (Huai) on the one hand, and countries 
which lie on the other side of the land-steps — Mongolia, Ordosland, and 
Schen-si (Shen-si), on the other hand. In southern China the separ- 
ating influence is veiled by the much stronger one that is exercised by 
increasingly high mountain ranges. 
B. RELATIONS OF THE ARE.\S OF THE E.\KTH"s CRUST WHICH BORDER THE 
SECTIONS OF CRESCENTS TO ITS INTERNAL STRUCTURE. 
a. The following are certain peculiarities of the internal structure of 
those areas in east Asia which come here under consideration : 
I. Fundamental gneiss and gneiss granite in the basement are found 
in China only in Schan-timg (Shan-tung) ; the internal structure show- 
ing the constant strike direction of N. N.W. — S. S. E. Obrutschew 
determined it in the ancient gneiss to the eastward of Baikal as W. N. 
W. — E. S. E. In all other Archean rocks of continental east Asia, which 
lie to the eastward of the meridian 105° East and to the northward of the 
Tropic, the Sinian strike direction (average \V. 30° S. to E. 30° N.) ap- 
pears to predominate strongly and to control regionally the basement 
structure. Only one important exception is known ; it is afforded by 
the relatively narrow but compactly constituted Tsin-ling zone in whose 
structure the Kii'oi-lun (Kuen-lun) strike direction (W. by N. — S. 
by E.) controls exclusively. This zone of intense folding must have 
