Memoranda on the Geology of Sikkim. 523 



Ruttoo and Reshee till the tributaries of the Rumam are 

 reached^ gneiss mountains are only met with, and the coun- 

 try is there left in a state of nature. 



In the Bellassur valley, the cultivation may also be consi- 

 dered to mark the elevation to which the aluminous soils 

 rise. On the east side of the Sonada range, the mountain 

 under Mahaldarem is too steep to admit of cultivation being 

 attempted on it high up, and we had made a march and a 

 half down the hill before we came on slate in situ: as we 

 approached the Munna or Mahanuddee we met with sand- 

 stone^ slate and sandstone are also found on the Rektee, and on 

 the small streams about Punkabaree, and on the low hills in 

 its neighbourhood ; and at that place and above it till half-way 

 to the level on which Kursiong Hotel stands, mica slate 

 abounds, and forms the outer covering rock of the mountani. 



From the junctions of the small Rungeet and great 

 Rungeet to the junction of the latter with the Teesta, slate 

 occurs, and down the valley of the Teesta, by Sideongbleoo, 

 Dimma and Britgong, the country presents a slate formation. 

 On the Subbok, clay stones and sandstones occur. 



From the Munna over Sutong, across the Rieng over 

 Mungpo, across the Rungzo up Rienghien-yon-lot, and till 

 well up Sinchul, we meet slate. At Rienghien-yon-lot the 

 country bears marks of having been extensively under culti- 

 vation not many years ago. 



The minerals met with by me in the Sikkim hills are gneiss 

 rock in the highest positions, and it is also found protruding 

 through slate at the elevations where that rock occurs in 

 many places, as on Rinchonpoom, where abrupt masses of it 

 with a weathered look remind one of the storm-beaten rock 

 seen on sea coasts in other regions. To me the dip of the 

 gneiss seemed generally, if not miiformly, to be back from the 

 valley from 15° to 20° by the eye. This is seen in many 

 places, but no where more clearly than at Boodam, Seguar, a 

 precipice in the valley of the Boodam, a tributary to the 



