PERMO-MESOZOIC INTRUSIONS. 91 



folding. In the section observed by L6czy, in longitude 106 east, in that 

 previously observed by von Richthofen in longitude 107 30' east, and in 

 that of the expedition of 1903-04 in longitude 108 15' east, there are areas 

 of slates, argillites, schists, and gneisses, apparently derived from Paleozoic 

 sediments and associated with large masses of intrusive diorite or granite. 

 In the last-named section two large granite masses and several smaller ones 

 present a total width of 19 miles in 84 miles. They are intrusive bands, 

 whose length along their trend parallel to the axis of the range is very 

 considerable. Their effect in altering adjacent strata is extremely variable, 

 the limestone of the Hei'-shui series near lyiu-yiie-ho (atlas sheet a 2) being 

 but little affected a hundred feet from the contact, whereas near Ssi'-mou-ti 

 (atlas sheet a 3) the Paleozoic strata are generally and intensely metamor- 

 phosed, although the intrusions as they appear at the surface are much 

 smaller. 



The date of these intrusions is later than the folding, as the holocrys- 

 talline intrusive rocks were not sheared, but it is presumably not much 

 later. Among the intruded and metamorphosed strata we believe we have 

 identified the K'ui-chou formation, i. e., Permo-Triassic, which may have 

 been contemporaneous with the early effects of deformation, but which was 

 involved in the later effects to the extent of overfolding and overthrusting. 

 And unconformably above the metamorphosed strata occur the unaltered 

 Shi-ts'uan sandstones, which we correlate tentatively with the middle or 

 upper Jurassic sandstone of the Red Basin of Ss'i-ch'uan. These data seem 

 to confine the episode of intrusion to the Triassic or early Jurassic, to the 

 close of the period of diastrophism. The inference is strengthened by the 

 fact that there are not any Cretaceous or early Tertiary sediments of marine 

 or continental character, such as should occur as a result of erosion if, 

 during those periods, there had been great intrusions of granite, with the 

 probable accompaniment of decided elevation. 



The region within which the early Mesozoic intrusions occur is not yet 

 well defined. In the western Ts'in-ling-shan, between longitudes 107 and 

 1 08 east, the zone may be said to extend from the Wei' to the Han valleys, 

 between latitudes 33 and 34 10' north. In longitude 109 30' its southern 

 margin is near Chon-p'ing-hie'n, latitude 31 50'. The eastern and north- 

 eastern extension is indefinite, as the great granite masses of the eastern 

 Ts'in-ling-shan, which may in part belong to this period, are described 

 by l,6czy and von Richthofen as "Archean." Toward the northwest, in 

 longitude 105 east, latitude 35, near "Kun-tschang-fu" Loczy * observed 

 intrusions of granite in mica, amphibole, and chlorite schists. The occur- 

 rence is one of many granite masses which characterize the northwestern 



*Reise des Grafen Szchenyi, vol. I, p. 425. 



