PERMO-MESOZOIC. 8 1 



series lie north of that sea, on the continent of Angara. It is probable 

 that the continental area extended from the Gobi region of central Asia, 

 eastward to the present coast line or beyond it, and southward beyond the 

 site of the Ts'in-ling-shan, south of which it was bounded by the Tethys. 

 We thus place in the Angara series the terranes which are about to be 

 described. 



Strata which are assigned provisionally to horizons ranging from Per- 

 mian to Rhaetic, inclusive, are widely distributed in China, from Shan-tung 

 on the east to Mongolia on the west and from Shan-si in the north to Indo- 

 China in the south. The identification of the coal-bearing series as Rhaetic 

 rests on fossil plants and is usually qualified by an alternative assignment 

 to Lower Jurassic. Without attempting to prejudge the definite correla- 

 tion these formations are discussed in this section. 



In central Shan-tung observations by the expedition of 1903-04 with 

 reference to Permo-Triassic strata were made in the vicinity of Lai-wu-hien, 

 and are described in volume i, in the chapter on stratigraphy under the 

 Sin-t'an District. They are much less complete than is desirable, since our 

 attention was given chiefly to the older rocks, and in the sections which we 

 could conveniently observe there were gaps covered by alluvium at those 

 points where we should expect the passage from known Carboniferous to 

 supposed Permian. Carboniferous beds, identified by marine fossils in a 

 bituminous limestone interbedded in the coal-bearing sandstones and shales, 

 were followed by red cross-bedded sandstones. On account of their color 

 we have regarded the latter as Permian, and we take them to be of fluvia- 

 tile origin. Succeeding these, but in interrupted succession, occur red, black, 

 and greenish shales interbedded with basaltic flows. There is 

 evidence that throughout an area including practically all the central 

 of Shan-tung there was a volcanic district from which eruptions w 

 numerous and extensive. The activity began probably during the latest 

 Paleozoic and continued well into the Mesozoic. In volume i these vol- 

 canics have been classed with the Carboniferous, that systematic term 

 being extended to cover the Permian. 



Overlying the volcanic series near Yen-chuang, Shan-tung, occur beds 

 designated by us as the Sin-t'ai series, and by von Richthofen and Lorenz 

 assigned to the Jurassic. In the Sin-t'ai area they are exposed with a 

 thickness of several thousand feet, as gray to red sandstones and shales 

 with thin beds of conglomerate. Von Richthofen included with them the 

 adjoining coal-bearing rocks of Ts'ai-kia-chuang (" Tsing-ko-tschwang ") , 

 but on the evidence of the plants collected Schenck placed the coal-measures 

 of that locality in the Carboniferous. 



In the coal basin of Wei-hien von Richthofen observed the occurrence 

 of coal-beds in close proximity to granite, an exceptional relation, since 



