J. S. Lee—An Outline of Chinese Geology. 325 
younger than the Sinian, nor could it be regarded as belonging to 
the Old Gneiss and Gneiss-granite group. They are apparently 
equivalent to similar strata occurring in eastern Shan-tung and 
Liao-tung.t. In descending the Wutai-shan along its southern 
flank, Richthofen first came across a thick series of green schists with 
alternating beds of grey slates and quartzites, and then several series 
of coarse quartzitic and felspathic well-stratified rocks, aggregating 
toa thickness of more than 5,900 feet. He calls the whole sequence 
of these strata the “‘ Wutai Formation”’, and parallels it with the 
Huronian. This term at once found a wide application in Chinese 
geology. Thus in the western Tsing-ling Range, south of Lio- 
yang-hsien (about long. 106° E., lat. 33° 25’ N.), and in the high 
mountains west of Ta-tsien-lu (about long. 102° 10’ E., lat. 30° N.), 
Loczy distinguishes a series of highly metamorphosed sedimentary 
rocks, such as gneiss, schists, phyllites, crystalline limestone, etc.,* 
and assigns it to the Wutai Formation. The ‘“‘ Nan-shan Sand- 
stone ’—a series ofunfossiliferous grey and green sandstones with 
well-cleaved or even schistose clayslates, typically developed in the 
northern foothills of the Nan-shan Ranges—is also tentatively 
regarded by the same author as a Wutai Formation. Between 
Ping-liang and Men-chou, in the province of Kan-su, Futterer 
identified in several places the Nan-shan Sandstone, and found other 
metamorphosed sedimentary strata of the Wutai Formaticn, 
consisting of chlorite-schist, coarse-grained quartzite, slate, and 
graywacke. In all these cases the term Wutai evidently implies 
the analogy with the Algonkian of North America. 
As the result of field observations in the adjoining area of Shan-si 
and Chi-li,? particularly in the Wutai district, Willis and Black- 
welder were able to recognize two systems of rocks of pre-Cambrian 
age: the lower or the Wutai System rests unconformably upon the 
Tai-shan Complex, and the upper or the Nankou (Huto) System is 
believed by the same authors to overlie unconformably the Wutai 
System. They further state that the unconformable junction 
between the Huto and the Wutai may be seen on the top of the 
Nantai-shan. This statement has been, however, not yet confirmed 
by published reports of field observation in the Wutai district. 
What may be regarded as a case supporting this inferred strati- 
graphical relation is a photograph in the Record of the Work of the 
Geological Institute, showing the Nankou (Huto) System resting 
unconformably on the Wutai strata in the Chien-an district, north- 
eastern Chi-li. 
The Wutai System is well developed in the south-eastern flank of 
the Wutai-shan. Willis and Blackwelder divide it into three series 
in the following descending order :— 
1 China, vol. 1i, pp. 106, 107, 215-17. 
2 Loczy, op. cit., vol. i, pp. 428-65, 692-726. 
3 Willis, op. cit., vol. i, pt. i, pp. 99-135. 
