94 NEW YORK STATE MUSEUM 



vertex of Asia into two directions, which we will find to extend 

 over the greater part of Eurasia. 



Richthofen found that the Precambrian basement complexes in 

 East Shantung, Liantung, 1 Korea etc., which are overlain by flat 

 Cambrian and younger deposits, everywhere display a strong 

 folding which is mainly directed northeast. Also in the region 

 north of Nanking wherever the Precambrian (Archeozoic and 

 Proterozoic) rocks appear from below the old table-land, they hold 

 the same position. A like direction had already been recognized by 

 Pumpelly (1866) to be a general law for the mountain ranges of 

 eastern China. He had termed this system the Sinian system of 

 mountain folds. Richthofen (1882, p. 637) concluded from the 

 parallelism between the Precambrian folds, that were already 

 abraded again before Cambrian time, and the later folds of the 

 Sinian system, that new folds (or also faults) in an already folded 

 country are apt to follow the old trends. We shall refer to the 

 significance of these so-called " posthumous folds " in another 

 place. 



Suess has repeatedly (in volumes 2 and 3) depicted the structure 

 of " Angaraland," the ancestor of Asia, and it is not necessary for 

 us to go here into details. After showing that entire eastern China 

 and Siberia are controlled by the Sinian direction, which already is 

 established fully in the Precambrian basement complex, Suess 

 proceeds to demonstrate, mainly from the publications of I. D. 

 Tscherski (1886, 1889) that the folds of the ancient Precambrian 

 mountains in the amphitheater of Irkutsk, east and west of Lake 

 Baikal, strike in opposite directions and converge toward the south 

 (see figure 1) . The northeast or east-northeast strike which exists east 

 of Lake Baikal he terms, after Tscherski, the Baikal direction, and 

 that to the northwest or west-northwest which prevails west of the 

 lake, the Sayan direction. Between these two principal regions the 

 folds become crowded together and acquire a more or less north 

 to south direction and it is evident that the folds were pressed inward 

 or toward the axis of the amphitheater. This amphitheater is 

 the exposed Precambrian area of the ancient vertex of Asia. A 

 younger vertex developed later in the Altai, and from this proceeded, 



1 While Suess considers in volume 2, page 231, the northeast direction as the 

 principal one, it is stated in a note (ibid., p. 254), that Richthofen observed in 

 several places still another direction which is recognizable in the oldest gneiss, 

 while the younger mica schists, marbles etc. strike in northeast-southwest 

 direction. In volume 3, part 1, page 256, Suess accepts the steady north-north- 

 west direction of the older gneisses in Shantung and Liantung as the principal 

 and hence an irregular one, but adds that in the adjoining provinces of North 

 Tshili and North Shansi, which lie nearer to the Gobi desert, the regular east- 

 northeast trend controls again the Precambrian folding. 



