472 Extracts from the Proceedings of the British 



but seen in the northern province of Moulmein, I have provisionally 

 called it the " Moulmein " series. To determine the age of the 

 older of these two groups (the Mergin) we have no data. The 

 aspect of much of the rocks is very similar to the trappean ashes 

 and . felstones so abundant in the silurian rocks of this country, 

 while others are lithologically like Devonian; but these resem- 

 blances are very deceptive. The age of the Moulmien series is, 

 however, tolerably defined by its organic contents. These appear 

 to fix the age of the group as distinctly carboniferous. The whole 

 of these rocks were, subsequently to their induration and disturb- 

 ance, widely and greatly denuded, and on their upturned edges a* 

 intervals is found a series of conglomerates and sandstones and 

 imperfectly coherent shales, with thick beds of coal, generally of 

 lignitic character. None of the conglomerates are coarse ; the 

 sandstones are fine, gritty and pebbly, or clean white quartzose . 

 grits ; the shales thinly' laminated ; the coal itself thinly disposed 

 in thin flaky laminae, with earthy streakings marking its structure- 

 In addition to the total unconformity of these rocks, the imbedded 

 organic remains are quite distinct. They consist of dicotyledon- 

 ous plants (leaves) belonging to the group of the Laureacese, and 

 probably to the genus Laurophilum of Goppert. In the thin pa- 

 pery shales which overlie the coal are also remains of fish (scales, 

 &c.) of fresh-water character; the whole referring the beds to a 

 very recent epoch, probably corresponding in part to the pliocene 

 of European geologists. It is curious to notice here the absence 

 of any coal in the carboniferous rocks below^, and its abundant 

 presence in those newer beds. The total thickness of these beds 

 does not exceed 900 to 1000 feet. They are never continuously 

 traceable; they occur heaped up against and separated by the 

 projecting ridges of the higher ground, and must have been de- 

 posited when the physical conformation of the country was very 

 similar to that now existing. They appear to be the result of a 

 series of fresh-water deposits, formed in small lake-like expansions 

 along the lines of the great drainage valleys of the country, and 

 to' mark a line of general and greater depression between the main 

 ridge of liills dividing Siam from the British dominions, and the 

 outer ridges which occur between this and the sea. The direction 

 of the main drainage of the county is determined, as already re- 

 marked, by the direction of these ranges, and is discharged into 

 the sea through narrow rocky gorges, which have a direction 

 nearly into the east an. I Avest, aud which are due to lines of break- 



