DA LING AND DARJ1LING SERIES. 41 



the fissile planes, showing 1 that the latter are due to foliation, not to cleav- 

 age. These slates pass insensibly into ordinary clay slates, more or less 

 earthy or silvery according to the degree of alteration they have under- 

 gone. There are also bands of quartzite and quartz flags, and occasion- 

 ally some of hornblende schist. The latter are sometimes slightly 

 calcareous, or composed of actinolite with magnesian carbonate of lime 

 between the crystals, and this rock even passes into impure dolomite con- 

 taining much actinolite. Such beds are, however, very rare and insignifi- 

 cant. The almost complete absence of lime in the Daling beds is one 

 of the most prominent lithological distinctions between them and the 

 Baxas ; another is the rarity of brilliantly-coloured alternations of slate, 

 like those in the Titi naddi section, the colours of the Daling slates being 

 less variegated and more sombre. 



The sections west of the Mahanaddi do not show much of the light 

 green slate, so prominent to the east of that river ; along the cart road, 

 for instance, they are more earthy and arenaceous. I am inclined to 

 think that this is merely due to a difference in metamorphism, combined 

 perhaps with lateral change in lithological characters ; it may, however, 

 be of more importance, and connected with the disappearance to the 

 east of the slaty conglomerate which forms the base of the D&ling series 

 in the neighbourhood of Selim Hill. 



I have said that the Daling beds everywhere underlie towards the 



Ddling beds underlie g neisS ' Ahn § the 0uter faCe ° f the hills there 



the gueissose. ig not much difficu j tv £ n drawing a line between 



the two, for although there is always a passage from one rock to the 

 other, this passage is comparatively rapid. But as we ascend the valley 

 of the Tista towards the interior of the hills, the lower beds become 

 more altered, and frequently changed into mica schist and even gneiss, 

 whilst the gneiss cf the upper strata is often of an indefinite character 

 with much mica schist. The rocks colored blue about Kalingpung and 

 Damsang, and west of the Tista, frequently include bands which are 

 quite as much, or more, altered than others in the area colored pink. 



f ; ( 41 ) 



