Geology. 351 



vician of the Baltic region, a fauna that also greatly influenced 

 the make-up of the Mohawkian assemblage of the Mississippi 

 valley, migrating here by way of the Pacific ocean. 



The Sint'an formation (upper Ordovician to and including 

 lower Carboniferous), 2,000 feet thick, represents chiefly Silurian 

 time but no fossils were collected by the Willis party, the corre- 

 lation being made on the work of Kayser in Richthofen's China. 

 The Devonian has a calcareous, marly and bituminous character 

 and is of no great thickness. The Sint'an is said to be without 

 unconformities. During this time China was in a stable condition 

 without very high lands and devoid of great movements. 



Upon the older Paleozoic follows conformably the upper Car- 

 boniferous ; to these formations six pages only are devoted. As 

 in eastern America, so in China there are two, apparently contem- 

 poraneous, widely differing series of deposits. The one of north- 

 eastern China is essentially of a continental nature, sandstones 

 and shales with numerous coal beds, and thin zones of marine bitu- 

 minous limestones. The other is a single limestone formation in 

 places more than 4,000 feet thick. During the late Carboniferous 

 movements are again in progress, during which time the Kuen- 

 lung system of folds developed. The extensive mediterranean, 

 Tethys of Suess, is now in full development, depositing in Asia the 

 complete sequence of Permian and Triassic marine formations. 

 In northern Asia and Siberia is the continent Angara with its 

 fluviatile deposits, while to the south is the greater land Gondwana 

 with its Glossopteris flora. In all of central Shantung there was 

 volcanic activity, beginning during the latest Paleozoic and con- 

 tinuing well into the Mesozoic. It is also during this interval 

 that the various parts of Asia were still separated by the Hima- 

 layan strait. Mountains then developed " which are structurally 

 still the controlling features of Asia. The foundations of the 

 ranges are now raised to the summits of the Tien'-shan, Kuen-lung, 

 and Ts'in-ling-shan, and the substance of their masses constitutes 

 the Triassic and Jurassic sediment of Asia. By Cretaceous time 

 the continent was again low." 



" Nor are Cretaceous strata of any kind known in the vast area 

 of Asia north of Tibet, east of the Urals, and south of northern 

 Siberia. No other fact than this, perhaps, more sharply chal- 

 lenges the hypothesis that the present mountain ranges and 

 basins of central Asia date from a pre-Cretaceous time. High- 

 lands without waste and waste without deposit in these interior 

 basins are inconceivable ; .... in the latest Jurassic, Lower 

 Cretaceous, and Upper Cretaceous of nprthern India we have the 

 sedimentary record of the reduction, peneplanation, and partial 

 submergence of the continent, which in preceding Mesozoic time 

 had attained very prominent relief" (pp. 95-96). 



The principal continental upwarp of central Asia "appeal's to 

 fall chiefly within the Quaternary, but may extend back into the 

 Pliocene." " It is the time of one of the most remarkable dias- 

 trophic movements of which we have knowledge." 



