156 Proceedings of the Royal Irish Academy. 



It is also recorded that a violent eruption took place in the year 

 1757 in the sea three leagues distant from Pondicherry. An island 

 formed by it disappeared soon afterwards, having been eroded by the 

 sea,^ as was the case with Graham's Island in the Mediterranean Sea 

 in 1831. 



A passing reference may be made here to the volcanic phenomena 

 found in Burmah, and to the curious so-called mud volcanoes which 

 are however unconnected with true volcanic action, being more closely 

 related to those which cause hot springs. 



At Puppa Doung, about fifty miles N.N.E. of Ye-nan-Khyoung, 

 and thirty miles E.S.E. of Pagan on the Irawadi there is a volcanic 

 crater believed to be of Pliocene age which rises about 3000 feet 

 above the surface. It has long been extinct, as is testified by the 

 vegetation. The crater consists of a breccia of ash, and towards the 

 base there are flows of trachytic lava. 



The place is regarded by the Burmese as the home of Hats or evil 

 spirits, and probably there are traditions and myths connected with it,, 

 though I have not yet succeeded in meeting with any record of them.* 



The principal mud volcanoes are at Membu on the Irawadi, and 

 on the islands of Eamri and Cheduba on the Arakan coast. Those of 

 Pamri, of which there are about a dozen, are subject to violent erup- 

 tions and eject stones and flames. They consist of cones formed of 

 mud which has been ejected by the pressure of gas. The craters at 

 the summits contain mud in a viscid condition. The gas is the 

 ordinary marsh gas (carburetted hydrogen) ; with it petroleum and 

 saline waters are also ejected, but there is nothing indicating volcanic- 

 action, and the ignition of the gas is attributed to electricity induced 

 by friction of the gas and water through the vents. The mud cones 

 exist where the local strata consist of soft tertiary shales which are 

 softened by the action of the gas and water. The gas and petroleum 

 are believed to be derived from the fossil plants and animals in the 

 tertiary rocks in which these mud volcanoes are alone found. 



As regards the natives' opinions of these phenomena, and the 

 myths connected with them, the records are unfortunately incomplete^ 

 — they deserve special inquiry. 



1 Asiatic Annual Eegister, vol. i., 1758, and Jour. As. Soc. Bengal, vol. xvi., 

 1847, p. 499; Bomb. Geol. Soc, vol. x., p. 146. 



2 W. T. Blanford, J. A. S. B., vol. xxxi., 1862, p. 215, and Manual of the 

 Geology of India, vol. ii., p. 725. 



^ Described by Mr. F. R. Mallet, who incorporates the views of previous- 

 observers. — Rec. Geol. Survey, vol xi., 1878, p. 188. 



