140 OBSERVATIONS ON THE GEOLOGY OF THE 



picturesque appearance, and where the river washes their base, present 

 perpendicular cliffs of four and five hundred feet. They are even more 

 purely calcareous than the rocks at sea, for many look at a short dis- 

 tance, as if formed of chalk. This they owe to the agaric mineral. Tin 

 abounds in the granitic hills in the vicinity of this valley. The great hill 

 range of the Peninsula, was not observed from this point, owing to the 

 intervening rocks. But the Siamese chief informed me, that it must be 

 ct^ossed in the route thence to the opposite coast of the Peninsula. No 

 information could be expected from him, as to the rocks associated there. 

 The population here is about eight thousand souls, including six hundred 

 Chinese, and about one hundred Siamese priests of all ages. 



Passing to the northward of Junk-ceylon, the coast is bold for the 

 distance of a degree ; and lying about thirty miles otf this line, are nu- 

 merous calcareous perforated rocks, frequented by the edible birds' nest 

 gatherers. 



From all accounts obtained from native travellers — from personal 

 observation when sailing up the coast, and with reference to the narrow- 

 ness of this part of the Peninsula — it has appeared to me that the great 

 central range is here of less width than at any other point. But I 

 cannot admit, that this circumstance, as some have imagined, should 

 give any color to the supposition that any internal navigation is, or could 

 be, rendered practicable betwixt the Bay of Bengal and the Gulph of 

 Siam. I have before me native plans, in which the hills are laid down as 

 continuous. At any rate, the inclination of the countries towards the 

 Gulph of Siam on the one side, and the Bay of Bengal on the other, is 

 so great as to prevent the rivers which flow over them from being navi- 

 gable to good sized boats, beyond perhaps ten or twelve miles from their 

 mouths. 



The 



