STRATIGRAPHY OF SHAN-TUNG. 49 
iferous series from Shan-tung indicates that the interval of erosion may 
have included all of those periods, and thus be worthy of rank as an uncon- 
formity of the first magnitude. It is possible, however, that sedimentation 
may have continued long after Ordovician time, and that the resulting 
rocks were subsequently removed by erosion, in all the localities thus far 
examined. 
CARBONIFEROUS SYSTEM. 
The younger consolidated rocks which we encountered on our journey 
in central Shan-tung belong in part to the Pennsylvanian (Upper Car- 
boniferous) and in part, probably, to a later period (Fig. 12). At the 
base lies a series of coal-bearing shales and sandstones, near the top of 
which there occur volcanic flows, tuffs, and intrusions in varying amount.* 
These are followed by red and gray sandstones, shales, and conglomerates, 
which are believed to be of distinctly later age. For the coal-measures 
we propose the name “ Po-shan series,’’ on account of the important posi- 
tion which the city of that name has long maintained in the production 
of coal and in the manufacture of clay wares, the materials for which 
are secured from the coal-measures in that vicinity. 
PO-SHAN COAL-BEARING FORMATION. 
Exposures of the coal-measures were examined in the vicinity of 
Ts’ai-kia-chuang, Yen-chuang, and Po-shan, and they are known to occur 
also at Wei-hién,j I-chéu-fu,f and several other places in the province. 
IN THE SIN-T’AI DISTRICT. 
Stratigraphy.—The Po-shan rocks were first seen under somewhat 
unfavorable conditions, 2 miles, 3 kilometers, northeast of the village of 
Ts’ai-kia-chuang. Yellow, black, and gray shales and quartzose sand- 
stones are exposed in several shallow gullies, but not broadly or continu- 
ously. The thickness of the strata included in these shales and sandstones 
was estimated at something more than 1,000 feet, 300 meters. At many 
horizons the shales contain clay-ironstone nodules, but unfortunately these 
are not productive of fossils, as are similar nodules in certain parts of the 
United States. 
The only recognizable organic remains which we found were some 
imperfectly preserved plants, occurring in a coarse white sandstone, 
several hundred feet above the coal seam, which is now mined. While 
examining this same exposure more than thirty years ago, von Richthofen 
collected specimens of the fossil plants. Professor A. Schenk, in his 
Be fete perards the tuffs and other volcanics as Permian (loc. cit., p. 18). 
+ See von Richthofen, vol. 11, page 210. 
t Ibid., page 184. 
