96 RESEARCH IN CHINA. 



northern India we have the sedimentary record of the reduction, peneplana- 

 tion, and partial submergence of the continent, which in preceding Mesozoic 

 time had attained very prominent relief. 



TERTIARY AND QUATERNARY. 



A sedimentary record of the Tertiary history of China is wanting, as 

 is that of the Cretaceous. We turn to Indo-China, India, southern Tibet, 

 and western Asia, for occurrences of marine and estuarine deposits, which 

 by their calcareous or carbonaceous character show that the peneplain 

 conditions of the Cretaceous period were continued, at least in southern 

 Asia, through the Eocene and Oligocene and well into the Miocene. The 

 marine zone which was the southern branch of the Tethys persisted along 

 the Himalayan region and still divided the ancient Gondwana land of the 

 Indian peninsula from Tibet. The movements which, during the Oligocene 

 and Miocene, closed the strait, are described by Griesbach,* who, in a lim- 

 ited exploration of the Hundes plateau of southern Tibet, distinguished 

 altered nummulitic limestone, unconformably overlain by Miocene (?) sand- 

 stone, a few hundred feet thick, which in turn is conformably covered by 

 a great thickness of nearly horizontal beds that Lydekker determined on 

 the evidence of mammalian bones to be probably Pleistocene and certainly 

 not older than Pliocene. The recent observations by Hayden in the prov- 

 ince of Tsang and U along Younghusband's route to Lhasa have confirmed 

 Griesbach 's observations.! 



The evidence of stratigraphy north of the range agrees with that of 

 the Siwaliks of the southern foothills, and there is every reason to accept 

 Oldham's view that much of the elevation of the Himalayas has occurred 

 since the Miocene epoch. $ In view of the evidence that other mountain 

 systems of Asia have grown to great heights during the Pleistocene it may 

 be questioned whether the Himalayas reached their present altitude during 

 the initial movements of folding ; it is even probable that they have suffered 

 one partial epoch of erosion to advanced maturity and have since been 

 warped up, as have the Apennines and Karpathians; but they in any 

 case represent the latest effects of the compressive force which has welded 

 Asia into a continent. 



History repeats itself, now here, now there. The northern Tethys 

 was closed by a late Carboniferous movement, during which the Kuen-lung 

 system of folds developed; and the supra-Carboniferous sandstones were 



*Central Himalayas, Memoirs G. S. I. xxm, pp. 82-87. 



fGeology of Tibet, Rec. G S. I., 1905. 



J Manual of Geology of India, second edition, 1893, p. 479. 



Studies in Europe, B. Willis, Year Book of the Carnegie Institution of Washington No. 4. 



