12 GEOLOGY. 



the mountains, claystone porphyry in a very indurated state, is 

 found more than a thousand feet above the valley below. This 

 is succeeded by clay state, and grey quartz rock, or green- 

 stone slate, and then granite i3 again seen at perhaps two 

 thousand feet above Hhe sea. 



After leaving the granite on the northern route by Lokekhyen, 

 the first rocks that appear are different varieties of indurated 

 or silicious slate. On the summit of the ridge which divides 

 the waters that fall into the sea from those that pour into the 

 Tenasserim, greenstone slate appears again, weathered on the 

 outside for nearly an inch deep into a rock resembling red 

 sandstone, or some varieties of laterite. On the summit of 

 this ridge, which has a little table land, a narrow vein of 

 granite obtrudes in a fine grained porphyrinic rock. The 

 vein is not more than half an inch wide and consists prin- 

 cipally, if not altogether of mica and quartz, the former in the 

 greatest abundance ; and the rock which the vein pierces, seems 

 to consist of the same minerals but contains numerous crystals 

 of mica diffused throughout, that appear to have been formed 

 there when the vein was ejected, for they are most numerous 

 nearest the vein. 



On descending the mountains into the valley of the Tenas- 

 acrim, indurated clay slate, and quartz rock are repeatedly seen, 

 and on these rests a white sandstone. At the foot of the 

 mountains for a space of about six or eight miles long by three 

 or four miles wide, is a diluvial deposit six or eight feet deep, rich 

 in tin, and containing a little gold. 



When the banks of the Tenasserim are reached a few miles 

 east of the diluvium, a succession of beds of conglomerate or 

 pudding stone are seen, consisting principally of rounded 

 pebbles cemented by the hydrate of iron. They are inclined 

 at a small angle with the horizon, and dipping towards the 

 west and north, lean towards an anticlinal axis east and south. 

 A few miles north of this locality, and lying above the con- 

 glomerate are beds of clay containing lignite. 



Descending the river to the high banks at the forks of the Ten- 

 asserim, beds of indurated sand are seen cropping out beneath 

 the conglomerate, which abound in impressions of leaves of 

 dicotyledonous plants resembling the leaves of existing species, 

 and below these, down to the water's edge are beds of shale 



