22 RESEARCH IN CHINA. 



Another series described by L6czy, which belongs in this category, is 

 that which he designates early Paleozoic limestones. He says :* 



At several points in the range of the Nan-shan I found light-colored, d'ense, half- 

 crystalline, sometimes siliceous, dolomitic limestones. Everywhere the limestones occur 

 in moderately thick strata, conformably bedded with the Nan-shan sandstone, either inter- 

 bedded or in the form of "Klippen." In none of these limestones could I find fossils, even 

 in numerous thin sections. The investigations of Dr. Konrad Schwager of the material 

 sent to him likewise yielded a negative result. Lines which might suggest bivalves, a 

 spheroidal inclusion with a tangled, reticulated character, and a globulitic structure, occa- 

 sionally suggest an organic origin. 



At the time that L,6czy and Obrutchov wrote their descriptions they 

 could compare the formations which they had observed only with the 

 Archean, the Wu-t'ai or Huronian, and the Sinian. According to von 

 Richthofen's definition, the latter comprised strata conformably under- 

 lying the Cambrian, which might therefore be considered the most ancient 

 Paleozoic deposits. In distinguishing the Nan-k'ou or Hu-t'o system as a 

 pre-Cainbrian series, separated from the fossiliferous beds by an uncon- 

 formity and characterized by highly siliceous limestones and slight meta- 

 morphism, we have found a series which closely resembles the rocks which 

 Ivoczy designates early Paleozoic. As the limestones to which he thus 

 refers are interbedded with the Nan-shan sandstone, some part of that 

 system is also probably to be referred to the Nan-k'ou (Hu-t'o) terrane. 



Among the more highly altered metamorphic schists, quartzites, 

 and crystalline limestones, there may probably be found the representa- 

 tives of the Wu-t'ai system. It would not be surprising if outcrops of 

 these ancient formations should be found to lie in 'one or more rudely con- 

 centric arcs corresponding to the strike of the mountain ranges, which 

 extend from the type locality, the Wu-t'ai-shan in northern Shan-si, through 

 southern Shan-si and across Shen-si and Kan-su to the Nan-shan in Tibet. 

 This is the outline of the continental region during the succeeding Sinian 

 age, and it would be in accord with the general laws of relation between 

 continental structure and mountain trends that representatives of the 

 Wu-t'ai system should be found at intervals along this arc. 



In his southward journey from the northern Tibetan regions where the 

 Nan-shan sandstone is typically developed, through western Yiin-nan to 

 Burmah, L,6czy observed formations which he correlates with it.f They 

 occur chiefly between Ta-tsie"n-lu and Ba-t'ang in the outer ranges of the 



*Reise des Grafen Szchenyi, vol. I, p. 651. 

 \lbid., vol. I, p. 724. 



