32 RESEARCH IN CHINA. 



Archean strata and the Korea granite, as is clearly proven by the uniform occurrence of 

 the wide-spread covering of Sinian sediments. The surface was not, however, perfectly 

 uniform, as the eroding force could not overcome the resistance of the hardest rock. The 

 quartzites stand up in high reefs, as we have seen in Liau-tung at Sai-ma-ki a-nd Ta-ku-shan. 

 The Korea granite stands out occasionally in steep high bluffs, and yet in the immediate 

 vicinity it occurs as the surface of a plain of abrasion on which Sinian strata lie in horizontal 

 and undisturbed position. The irregularity of the action appears especially about the hard 

 cores of gneiss in the mountains. We have seen how the layers of the principal mass of 

 gneiss, which, around the Yellow Sea, strike north-northwest south-southeast and dip 

 steeply, were involved in the thrust in the Sinian direction and thrown into disturbed 

 positions which probably facilitated erosion, while near these deeply eroded and decom- 

 posed masses wild ridges of unweathered gneiss stand up. We must consider them the 

 massive cores which were not destroyed by the surf. They form the characteristic moun- 

 tains of eastern Shan-tung and Liau-tung.* 



The view that notable elevations were cut away by the waves is not 

 tenable in contradiction of the evidence of Sinian sediments. Where waves 

 do attack bold coasts of gneiss, granite, schists, and quartzite, they spread 

 coarse deposits of the obdurate rocks. Where large masses are rapidly 

 leveled by subaerial erosion or marine abrasion, sediments of corresponding 

 volume gather in some adjacent basin. The Sinian deposits do not repre- 

 sent either of these conditions. They are neither coarse nor voluminous. 

 They are frequently fine-grained calcareous shale or thin-bedded limestone 

 at the very base. The mechanical sediment of the basal formation has the 

 character of a fine alluvium and is of uniformly moderate thickness, 350 to 

 500 feet, 105 to 150 meters. The material is red soil, particles of ferrugi- 

 nous clay being thoroughly oxidized and grains of sand coated with ferric 

 oxide. The plane of contact at the base is sharply defined, usually very 

 even, not broken by abrupt hollows or decided projections, but swelling 

 gently over rounded bosses of the harder rocks. Pebbles of the subjacent 

 rocks are wanting in the basal deposits, as a rule, and where they occur are 

 limited to very local accumulations. Beds of arkose have not been seen, nor 

 even beds of clean sand such as waves usually spread. Thus none of the 

 effects of violent breakers are present; the evidence is that a gentler agent 

 cleaned the surface of the ancient rocks. The facts support the view that 

 the lowest strata of the Man-t'o formation were laid down in the shallows, 

 lagoons, and flood-plains of a very low, flat coast, where weak waves, feeble 

 shore currents, and rivers interacted. 



The smooth surface of the old rocks is one which has been swept clean, 

 as by the wash of little waves or by the wear of a stream engaged in lateral 

 corrasion. It is probable that a layer of saprolite was removed in the 

 process. The material laid down on the bared rocks is usually mud, occa- 



*China, "vol. n, pp. 710^711. 



