I38 NEW YORK STATE MUSEUM 



in China and (west-northwest direction) in southern Russia. The 

 same component is recognizable in the Variscan and Armorican 

 folding which also, as we noted before, may contain in its character 

 a strong posthumous element. In North America the east- west 

 component appears in the Precambrian folding of northern Quebec 

 where Cooke found the east component strongly prevailing over 

 the other north component ; but it is most apparent in the east-west 

 strike of the Precambrian folding in the middle zone of the continent. 

 On the southern hemisphere it is indicated by the east-west Pre- 

 cambrian and later folding of South Africa and the curving into 

 more or less latitudinal direction of the Andean folding in Argentina. 



These two belts, the northern belt of northwest and northeast 

 directions and the equatorial belt of north- south directions of the 

 Precambrian rocks are the two outstanding features of the trend 

 lines of the Precambrian rocks. 



It is significant that the Paleozoic continental platforms were 

 characterized, in contrast to the present continents, by their latitu- 

 dinal rather than their longitudinal arrangement, a fact pointed out 

 by Schuchert (1916, p. 91). 



It is further noteworthy that the great Tethys sea which formed 

 an east-west sea extending from Central America eastward across 

 Eurasia to the Pacific (see charts of Paleozoic continents and seas), 

 separates the two belts of folding and thus indicates a zone of either 

 less distinct or of transitional fold directions which also became 

 one of weakness, geosynclinal sinking and subsequent local folding 

 in Postpaleozoic time, which later folding has effectively hidden 

 and obliterated the original Precambrian folding. If one enters 

 the trend lines of the Precambrian rocks upon a polar projection, 

 instead of the Mercator projection, it is more distinctly seen that 

 the belt of the northern hemisphere, while distinctly circumpolar, 

 has a somewhat zigzagged course, resulting from two deep embay- 

 ments. These occupy the positions of the Pacific and middle 

 Atlantic oceans (Poseidon ; see Cambrian chart) ; their location 

 makes it entirely probable that they, as the loci from which the folding 

 pressure originated, supplied the northern components in the north- 

 west and northeast directions on both sides of the embayments. 

 In western North America the large Archi-Pacific ocean was able 

 to overcome entirely even the east-west component of the trend 

 lines. 



In the case of the north-south folding of the entire equatorial 

 or Archi-Gondwana belt, it is clearly difficult to try to explain 

 this solely by the influence of the Pacific ocean that interrupted 



