THE RED BASIN OF SZECHUAN 65 



inland lake with a fairly even floor. Since the draining off of 

 the waters the Yangtsze River and its network of tributary 

 streams have eroded channels 1500 to 2500 feet deep through 

 these soft sedimentary rocks, and converted the whole basin 

 into a thoroughly hilly country. To-day practically the only level 

 area is the Plain of Chengtu, some 80 miles long and 65 miles 

 wide, with an average altitude of 1800 to 2000 feet above sea- 

 level. The rest of the basin is broken up into a network of 

 low, rolling or flat-topped mountains averaging about 3000 

 feet above sea-level, and nowhere exceeding 4000 feet altitude. 

 The whole of this region is under agriculture, the highest 

 development of which obtains on the Chengtu Plain, perhaps 

 the richest area in the whole of China. Anent this particular 

 part we shall have something to say later. 



How great a period of time has elapsed since the disappear- 

 ance of the waters from this basin is purely conjectural. But 

 that this triangle has long constituted a well-marked boundary 

 is evidenced by the fact that remarkably few of the plants 

 found in the mountains bordering the eastern limits at 2000 

 feet altitude and upwards are common to the mountains 

 bordering the western limits. The genera are of course the 

 same, but the species are usually distinct. The difference 

 between the floras of the eastern and western border-ranges is 

 too great for a mere 500 miles of longitude to account for 

 solely. The same is true of the fauna in so far as the game 

 birds and animals are concerned, as Chapters XI and XIII, 

 Vol. II, dealing with these will confirm. 



From evidence presented by the flora to-day it appears 

 doubtful if ever the Red Basin was covered with great forests. 

 Rather would I suppose that subsequent to the disappearance 

 of the waters the region bore some resemblance to the " bad 

 lands " of certain parts of the United States of America. 

 All this is admittedly pure conjecture. Everjrwhere to-day, 

 trees, shrubs, and herbs are common, but the flora, in contra- 

 distinction to that of the contiguous regions, is relatively poor, 

 and the species largely common to the entire basin. Further, 

 the majority of these species are widely spread throughout 

 the warmer low-level legions in China, some indeed ranging 

 to the extreme eastern limits of the country. A theory is apt 

 VOL. I.— 5 



