F. Kingdon Ward—The Land of Deep Corrosions. 211 
by rivers all flowing in one direction, leaving parallel mountain chains 
between. Why do the rivers all flow in one direction? Moreover, 
there is a significant curiosity about the courses of some of these 
rivers. The main lines of drainage run due south, parallel to the 
great ranges, since they cannot as a rule flow across them (hence 
the ranges antedate the rivers, or are perhaps contemporaneous with 
them). But why should the tributary streams throughout their 
greater lengths flow strictly parallel to the main rivers, finally turning 
abruptly at right angles to join them? This is true of the tributaries 
of the Mekong and Salween, and is even more pronounced in the case 
of the ’Nmai-hka. The explanation, I think, lies in the fact that the 
region is traversed by parallel lines of weakness, produced in a manner 
to be described presently, and it will probably be found that the 
tributaries turn at right angles to join the main rivers where a change 
in the character of the rocks occurs. 
Of the parallel rivers, the Mekong is the most easterly that 
continues its southern course to the sea. The Yangtze, after a series 
of remarkable loops, turns away to the east, thus snapping up all the 
rivers beyond which flow southward, and it has been suggested that 
it too, like the Mekong and Salween, once had an outlet to the south, 
through Indo-China. On what evidence that supposition is based 
I do not know, but a valley or series of valleys running southwards 
from Likiang, where the Yangtze abruptly ceases to flow southwards, 
to Tali-fu, now occupied by a chain of lakes and marshes draining 
south to the Mekong, of which the Tali-fu Lake itself is by far the 
most conspicuous, lends colour to the suggestion; there are also hot 
springs all the way along this shallow depression, and records of 
numerous earthquakes, leading to the belief that considerable crust 
movement has taken place here. The rocks are mainly sandstones, 
shales, and lhmestone—crystalline on the Tali-fu range. 
The big N-shaped bend of the Yangtze, at the end of its southern 
journey, just before it definitely sets out eastwards towards the Japan 
Sea, in the course of which it cuts diagonally across the Likiang 
range, not flowing round it as is shown on the maps, is peculiar, but 
by no means unique in this region. Here I need only remark that the 
fact of the river cutting across the range suggests that this portion of 
that river at least existed prior to the uplift of the lofty Likiang 
range; but it was not then necessarily the source stream of the 
Yangtze as we now understand that river. It is much more likely 
that the Chin-sha-chiang (reserving this name for the southward- 
flowing upper portion of the Yangtze) did actually continue 
southwards past Likiang, being subsequently beheaded by the upper 
course of the eastward-flowing portion cutting back westwards; the 
southern portion of the Chin-sha-chiang, being thus isolated from its 
source, ultimately disappearing. This would account for the abrupt 
change of direction of the Yangtze, but not altogether for the 
extraordinary double loop into which it bends itself, unless we 
suppose that the western loop was originally a tributary of the 
independent Chin-sha, the water of the latter being eventually 
diverted through the channel of the former to join the Yangtze. 
At any rate this peculiarity is shared by at least three other rivers of 
