THE MALAYAN ARCHIPELAGO. 85 



groups, viz., (1) plutonic rocks of the gabbro and serpentine class 

 with hornstoue veins, intruding into (2) a complex of micace- 

 ous, compact sandstone, shale, marl, and plastic clay, the whole 

 being overlaid by (3) raised coral-reefs. The sandstone banks 

 bear impressions of a Fucoid, Chondrites nicobarensis, Höchst, on 

 the plane of sedimentation, like the rock at Biô-kô-sha* on the 

 east coast of Taiwan. The plastic clay abounds in Foraminifers, 

 which belong to the Young Miocene. Geologically important 

 forms among them are Quinqueloculina, Bulimina, Lagena, Nodo- 

 saria, Orislellaria, Sphœroidina, Globigei'ina, and Orbulina. 



To the east of the first chain there lies another, which 

 begins near Bahrao in the Yunnan frontier, and extends south- 

 wards between the Irrawaddi and Sitoung rivers, the relief be- 

 coming lower in the Pegu region, until it becomes merged in 

 the sea between the Andaman group and the Malayan peninsula, 

 which is regarded as its continuation. The upland of Pegu is 

 of Miocene age (the Pegu division); the loose sandstones and 

 clay, of which it is built up, contain many small shark's teeth 

 besides a large Charcharias {Prionodon sp.), some two inches long, 

 together with Daphoderma caelata. Peeve, Peclen cf. favrei d'Arch. 

 and Haime, and Cardium sp. Squaline remains occur particularly 

 in the upper Miocene and in the basal member of the Pliocene 

 (the Irrawaddi division)^^ also. 



The region lying east of the Sitoung river seems to be 

 mainly Palaeozoic, and certainly proved to be in part Carboni- 

 ferous. Granites, old- looking sandstones and slates, so says Sie- 

 vers,'*^ extend down to Singapore, and thence to Banka, Billiton, 



* The village Biô-kô-slia = ÏS 4^ jfit- 



3) Noetling, loc. cit. p. 63. 



4) 'Asien.' 



