2 BURMA, ITS PEOPLE AXD PRODUCTIOXS. 



a belt of countr}' to tlio cnstwanl of tlip Jiowcr foniintions, correspondinn; willi tlie 

 nmin ranges oast of the Tsittounji;. Between the Tsittoung and the Salweeii the 

 gneiss passes into a true granite, which weathers down into remarkahle rounded 

 masses, whieh have been well described by the Rev. C. Parish, in his notes of a trip 

 lip the Salween (J.A.S.B. 1865, part ii. p. 13o). Horublendic gneiss is subordinately 

 associated with the above rock, and crystalline limestone is also not unconunon. 

 No crystalline rocks (connected with the present group) occur in Pegu or Arakan 

 ■west of the ranges separating the Tsittoung and Salween Kivers. 



THE MERGUI GROUP. 



Resting on the metamorphio rocks, and next in order of age, we find in the 

 southern portion of the Tenasserim Provinces, a great accumulation of pseudo- 

 porpliyritic beds, of sedimentary origin, the characteristic feature of which is derived 

 from the presence therein of imbedded fragments of felspar. From having as yet 

 only been detected in the neighbourhood of Blergui, the}' have been termed the 

 Mergui group. 1'lie rock in its normal form is earthy, but higlily indurated ; it 

 passes on the one hand into a slate, without the conspiouousl}' por])h_vritic aspect 

 produced hy the imbedded fragments of felspar, and on the other into grits and 

 conglomerates. With these grits, and resting upon them, are dark-coloured earthy 

 beds, finely laminated, associated with hard (piartzose grits. The thickness of this 

 group may be placed between 9,000 and 12.000 feet. Ko fossils have been hitherto 

 detected in it, and its age is uncertain, possibly Silurian. 



MAULMAIN GROUP. 



The beds of the last group in the Tenasserim valley are succeeded, in ascend- 

 ing order, by hard sandstones in either thin or massive beds, with thin earthy 

 partings, often finely laminated. The prevailing colour is reddish, and some of the 

 beds are calcareous. Over these sandstones occur grey shaly beds, also sometimes 

 calcareous, with occasional beds of dark sandstone, succeeded by soft sandstones, 

 thickly bedded with grey and pinkish shaly layers intercalated, and upon theso 

 a thick series of beds of massive limestone. The whole group is between 6,000 

 and 7,000 feet thick or more, and contains fossils throughout, though usuall}' in 

 too poor a state for precise determination. Sjiirifer and Produclus are the prevailing 

 fossils, and the group is of distinctly Carboniferous age. The upper limestone is 

 more than 1000 feet thick. It forms the conspicuous murally-scarped hills near 

 Maulmain, and ranges up tlie Salween valley into the Karen-ni country (of the 

 "Red-Karens") beyond tlie British frontier; and the same formation not im[)robably 

 forms part of the Mergui archipelago, many of the islands of which are known to 

 consist of limestone, resembling that in the vicinity of Maulmain. 



THE TRIASSIC GROUP. 



Next in point of age comes in, a small area of rocks in quite another part of 

 Burma, rocks of the Triassio ago being only known as constituting a triangular 

 tongue in the Arakan range, running down from the frontier to a point about 

 west by north from Prome. The beds of this age are perhaps between 5000 and 

 COOO feet in tliickness, the most characteristic of them being some white-speckled 

 grits, with intercalated shales and sandstones, which attain about 1300 feet in thick- 

 ness, in the Illowa River, thirty-five miles west of Thayet-myo. Towards the base 

 is a calcareous conglomerate and a rubl)]y limestone containing a Cardila and a 

 few Gasteropods, and probaJjly at about the same horizon. At some few other 

 spots occ\irs a blue limcstime. which has yielded the only ty]ncal fossil of the 

 groujj, Ilalobiu Lommcli, a Triassic bivalve of very wide distribution. 



