DEVONIAN SYSTEM : WETWIN SHALES. 



241 



thickness, which may be in fact wanting in some sections, and which are 

 conformable to the Silurian (Gothlandian) below and the Carbor_iferou3 above." 

 The bituminous and shaly character of the Devonian strata in 

 Yunnan and Central China, in contrast with the 

 ^ Transgression north- pure limestones and dolomites of the Shan States 



and the Malay Peninsula, suggests that the sea 

 of that period was more shallow and less open towards the north 

 and north-east, and that, as time progressed, the submergence that 

 resulted in the accumulation of the massive Plateau Limestones in 

 the southern portion of the ocean advanced northwards ; for the 

 Devonian beds of China are followed by a great thickness of lime- 

 stones which, at any rate in Yunnan, resemble very closely the 

 Plateau Limestone of the Shan States. This suggestion is in ac- 

 cordance with the statement of Bailey Willis {Of. cit., p. 67) that 

 the Carboniferous overlaps the Devonian, and in north-eastern China 

 rests upon the Ordovician ; and that it is towards the south and 

 south-east, in Shen-si, Ssich'uan, etc., that the Carboniferous is repre- 

 sented by a great thickness, over 4,000 feet in places, of 

 limestone ; whereas the strata of the same age in Shan-tung and 

 Shan-si consist of continental deposits of sandstones and shales, 

 with beds of coal and occasional thin bituminous limestones {Of. 

 cit., p. 72). 1 



Wetwin Shales. 



The village of Wetwin is situated at the base of the preci- 

 pitous scarp already mentioned, which the 

 ter S ordep n osrt nd rail way descends at about 12 miles east of 



Maymyo, and is built upon a band of shales 

 which may be seen in all the watercourses flowing from the scarp, and in 

 the cuttings along the surrounding roads and lanes (Loc. 29, C 4). 

 These shales somewhat resemble a hard and fissile 'Fuller's earth,' 

 and are very argillaceous, generally of a yellowish buff colour, 

 mottled with pink or dark grey to black stains, of a type that is v< ry 

 common at various stages in each of the formations that occurs in 

 Extent kh e Shan States. They have been traced 



from the west side of the village, where the 



1 The Devonian faunas as yet described from the Himalayan area are too scanty to 

 permit the statement of any definite conclusions regarding a possible connection 

 between that area, and Burma (VV. H. Hudlcston, Devonian fossils from Chitral ; 

 Qeol. Mag., Dec. IV, Vol. IX, pp. 3, 49 : V. K. Cowpei Reed, Devonian fossils from 

 Chitral, etcj Records, Gcol. Sup). Ind., Vol. XL1, Pt. 2, page 86). 



R 



