1859.] Botanical Notes. 4G7 



, Leaving Thonzoo we entered the Siamese State of " Kiouk- 

 Koung," and our course lay at first Eastward, then Northward and 

 Eastward, until, in seven days, we again reached our boundary on 

 the Houngdrau river. The country crossed in the interim consists 

 of a mass of limestone hills, whose height averages 2-3000 feet, 

 clothed from top to bottom with the densest jungle. Although 

 apparently of the same geological formation as the perpendicular 

 rocks before mentioned, they have a rounded outline, and are cover- 

 ed with a rich clayey soil, in some places of considerable depth, the 

 colour of the clay varying from red to yellow. 



Unless I am altogether mistaken in considering the rocks to be 

 geologically indentical, it appears strange that two contiguous por- 

 tions of the same formation should have so strikingly different an 

 outward character ; the one, that of interrupted chains of rock with 

 perpendicular faces, and singularly rugged and fantastic outline : 

 and the other, that of an ordinary mountainous district of alternat- 

 ing valleys and hills. It appears difficult to understand how one 

 portion could have been subjected to eruptive forces from beneath, 

 which would not have equally affected the other, seeing that they 

 are so close, some of the abrupt rocks actually running into the val- 

 leys of (what I call) the hilly portion ! 



The difference, however, in the direction of the strata may per- 

 haps be one cause of the marked difference in their form ; for, where- 

 as in the perpendicular rocks (as seen near Moulmein) the strata 

 dip at a considerable angle to the Eastward, in the hilly district of 

 Kiouk-Koung they are horizontal or nearly so ; and I imagine that 

 those rocks which present their edges to the action of the weather, 

 are more liable to be worn into a rugged outline than those whose 

 strata are horizontally disposed. 



It was sufficiently easy to observe the disposition of the strata, as 

 the beds of the hill streams form, generally, the only practicable, path 

 across this wild district ; and, in these water-courses, the streams 

 fall over a series of regular steps, formed by perfectly flat slabs of 

 rock overlying each other horizontally ; these slabs being often from 

 ten to twenty feet broad, and two or three feet thick. And that 

 they are Limestone was shown by the fact that small stalactites 

 were of frequent occurrence on the perpendicular faces of the steps 



