n the folds of Further India. Amongst these folded beds lie
trough-like depressions filled with the Mesozoic red sandstone which
lies unconformably upon the Palaeozoic rocks.

The present configuration of China is due, in a very considerable
degree, to faulting. The abrupt eastern edge of the Shan-si plateau,
where it overlooks the great plain, is a line of fault, or rather a
series of step faults, with the downthrow on the east; and von
Richthofen has shown reason to believe that this line of faulting is
continued far to the south and to the north. He believed also that the
present coast-line of China has to a large extent been determined by
similar faults with their downthrow on the east.

Concerning the structure of the central Asian plateau our knowledge is
still incomplete. The great mountain chains, the Kuen-lun, the
Nan-shan and the Tian-shan, are belts of folding; but the Mongolian
Altai is a horst--a strip of ancient rock lying between two faults and
with a depressed area upon each side. In the whole of this northern
region faulting, as distinct from folding, seems to have played an
important part. Along the southern margin of the Tian-shan there is a
remarkable trough-like depression which appears to lie between two
approximately parallel faults. (P. LA.)

_Fauna_.

China lies within two zoological provinces or regions, its southern
portion forming a part of the Oriental or Indian region and having a
fauna close akin to that of the western Himalaya, Burma and Siam,
whereas the districts to the north of Fu-chow and south of the
Yangtsze-kiang lie within the eastern Holarctic (Palaearctic) region,
or rather the southern fringe of the latter, which has been separated
as the Mediterranean transitional region. Of these two divisions of
the Chinese fauna, the northern one is the more interesting, since it
forms the chief home of a number of peculiar generic types, and also
includes types represented elsewhere at the present day (exclusive in
one case of Japan) only in North America. The occurrence in China of
these types common to the eastern and western hemispheres is important
in regard to the former existence of a land-bridge between Eastern
Asia and North America by way of Bering Strait.

Of the types peculiar to China and North America the alligator of the
Yangtsze-kiang is generically identical with its Mississippi relative.
Th