350 Scientific Intelligence. 



tation and accumulation are in progress now and are believed to 

 have been similar in past ages" (pp. 184, 185). 



One of the most striking results was the discovery in the gorge 

 of the Yang-tsi of a glacial tillite 120 feet thick, underlying the 

 massive, cliff, marine limestone of Cambrian age. " It is a green- 

 ish gritty clay-rock of hackly fracture, in which lie irregular 

 stones of various sizes and kinds with their long axes at random 



angles with the horizontal The stones range in size from 



sand-grains to blocks 50 to 75 centimeters in length, and there is 

 no suggestion of the assortment of the individual sizes. Coarse 

 and fine particles lie indiscriminately mingled and chaotic in 

 their arrangement. The forms of the majority of the stones 

 are subangular, i. e., angles are present, but are smooth and 

 rounded . . . the scratched stones found in numbers firmly fixed 

 in the green tillite, in such a condition as to show that they had 

 never been disturbed nor subjected to surface abrasion since they 

 were imbedded there in early Paleozoic time." 



In northern Shansi the Tai-shan basal coipplex of Archean time 

 consists of varied gneisses and younger intrusions (volume ii). 

 Above an unconformity follow two great systems of Proterozoic 

 time. The lower Wu-t'ai system, several thousand feet in thick- 

 ness, has three series of formations, each separated by an uncon- 

 formity. Basally the system begins with heterogeneous quartzose 

 and clayey rocks, that are more argillaceous in the middle series, 

 and finally calcareous above. It is the material of a complete 

 erosion cycle and in time may equal the duration of the Paleozoic. 

 Finally, the Wu-t'ai system was folded and intruded before the 

 time of the next system, the Hu-to. The latter is of late Protero- 

 zoic time, consisting of unmetamorphosed sedimentaries, chiefly 

 of slates with thin bands of dolomite, and siliceous limestone of 

 not less than 3500 feet thickness, followed by about 3,000 feet of 

 massive limestone with much chert in sheets. Then follows a 

 very long erosion interval during which time Asia was reduced 

 to a featureless continent. 



Over a fairly flat land with red soils there followed in north- 

 eastern China the very widely spread Sinian system of Von 

 Richthofen, beginning apparently late in lower Cambrian time 

 and continuing without break into the lower Ordovician. Basally, 

 there is a red and brown shale not unlike that of Permian and 

 Triassic time with thin layers of limestone, together having a 

 thickness of from 350 to 850 feet. Then follows an interbedded 

 series of limestone and shale having a thickness of from 900 to 

 1,000 feet, abounding in upper and middle Cambrian fossils. 

 Above is a series, chiefly dolomitic limestones, at least 2750 feet 

 thick, eroded at the top (caverns with iron ore) to an unknown 

 extent. But few fossils have been secured near the top of these 

 dolomites, and these indicate lower Ordovician time. In the 

 middle Yang-tzi Province, however, Blackwelder found above the 

 dolomites a soft green calcareous shale 200 feet thick, with many 

 fossils, described by Weller. These clearly indicate middle Ordo- 



