224: geological Society. 



vOEEDII^GS OF LEARNED SOCIETIES. 

 GEOLOGICAL SOCIETY. 



April 15th, 1908.— Dr. J. J. Harris Teall, M.A., F.R.S., 



Vice-President, in the Chair. 



The following communication was read : — 



' Notes on the Geology of Burma.' 

 By Leonard V. Dalton, B.Sc, F.R.G.S. 



The object of this paper is to present the results of geologi 



expeditions in the Irawadi Valley, carried out by the Author a 



Mr. W. H. Dalton between 1904 and 1906, and to correlate th 



observations with those made by previous writers, thus summariz: 



present knowledge of the geology of Burma in general and of 1 



Tertiary System in particular. The classification of rocks arri\ 



at is shown in the following table : — 



Feet. 



Irawadi Series 20,0U0(?) Pliocene 



A , r, • r Pegu Group 7500 Miocene 



A r.-ikan Series \ -o ^ ■ n onn,^ -o 



[ Jiassein Group 8000 Eocene. 



f( Cardita-BeHs Cretaceo 



Upper <{ Halohia-Tuhuestone Triassic. 



[ Shales and grits (?) 



Lower. Flaggy shales and sandstones (?) 



The oldest rocks, not comprised in the above synopsis, inelu 

 representatives of the Silurian, Devonian, and Carbonifero 

 S}* stems, but little of their detailed geology is known. T 

 Cardita-'Beds may be correlated with the Cretaceous of Indi 

 The ' Chin Shales ' of Dr. Nestling seem to form part of the Basse 

 Group, of Eocene age, which is of much greater thickness thf 

 hitherto supposed, and the group rests presumably more or le 

 conformably on the beds below. The fauna is chiefly shallo 

 marine in facies. These rocks flank the Arakan Group on hot 

 sides and in the south form the backbone of the range, where the 

 e been considerably metamorphosed. The Pegu Group probabl 



. 'laps the preceding and is regarded as of Miocene age, al thong 

 '- ■ fauna has many relationships with that of the French Eoceui 

 'na glohidosa is described as the first European Miocene specie 

 rded from Burma. Estuarine conditions came on towards th 

 close of Miocene time, and, in the estuary of the Pliocene precursc 

 of the Irawadi, anticlinal islands of partly-consolidated Miocen 

 materials were formed. Around, and eventually over these island 

 a great thickness of fluviatile deposits was laid down, correspondin 

 to the Siwalik Beds of the Indian Peninsula. Finally, post-Pliocen 

 denudation and upheaval revealed the Miocene islands as inlien 

 while the Irawadi has left its gravels in patches throughout th 

 region. A list of fossils is given, and the species new to Burma 

 some of them new to science, are described. 



