Association for the Advancement of Science. 471 



simply to report progress, and to show that something had been 

 done to elucidate the structure of India. Referring first to the 

 districts to the east of the Bay of Bengal, the Tennasserim Pro- 

 vinces extend for about six degrees of latitude along the east shores 

 of the Bay of Bengal. In breadth they seldom exceed more than 

 one degree of longitude. From Siam, on the east these provinces 

 are separated by an interrupted range^'of mountains, occasionally 

 rising to 7000 or 8000 feet high, but the general height of which 

 is to the north about 4000, diminishing in passing southwards to 

 3000 feet or less. The main direction of this range is north and 

 south : this being also the general direction of the coast line, of 

 the minor and outlying ranges of hills, and, therefore, of the 

 rivers. The geological structure is tolerably simple, although, at 

 first sight apparently complicated, from the great disturbances to 

 which the Rocks have been subjected. The central range is of 

 granite, occasionally, but not fi'equently of syenitic character ; 

 itself traversed by thick veins of large crystaline felspathic gran- 

 ite, and often along its outer edges, or near its junction with over- 

 lying slates, characterized by the presence of tinstone as an in- 

 gredient of the mass disseminated among the other mineral con- 

 stituents. This granite axis is succeeded by highly metamorphic 

 rocks of gneissic and micaceous character, themselves cut up by 

 numerous veins of granite, which, however, do not extend far 

 from the junction. Upon these is a great accumulation of bluish 

 and bluish -black earthy beds, thinly laminated, of thin-bedded 

 grits, and of pseudo-porphyritic rock, the normal character of 

 which is an earthy hard rock with small irregularly disseminated 

 sub-crystaline felspar, passing, on the one hand, into slates, and, 

 on the other, into grits, often coarse and conglomeritic. These 

 harder rocks form all the higher grounds of the outer ranges of 

 hills. This series being best seen in the southern province of 

 Mergin, has been provisionally called the " Mergin" series. The 

 total thickness is about 9000 feet. It is succeeded uncorformably 

 by hard sandstones in thick and massive beds, with their earthy 

 partings, generally of reddish tints, occasionally deep red and yel- 

 lowish. A few beds are slightly calcareous, and in the upper 

 portion a few thin and irregular bands of earthy blue limestone 

 occur. Above these rest about 200 feet of soft sandstone in thin 

 beds, upon which apparently rests the massive limestone of the 

 country so largely seen near to Moulmien. The thickness of the 

 ntire group is about 6000 feet, an 1 as some of its members are 



