BH6T MAHALS OF KUMAUN. I«;q 



dip south of Shillong camping ground, where the boundary between 



the silurian and upper haimantas is indicated by the red quartz 



shales (3). South of it one passes in succession over the various 



quartzites, purple beds, conglomerates and greenish phyllitic slates of 



the haimanta system. This system seems to swell out in thickness con- 



siderably, and there is a gradual passage down- 

 Gradual passage be- 10 



tween haimantas and wards into the rocks of the vaikritas. South of 



the vaikrita system. ,.., .... . ,. 



Milam a garnetiferous mica-schist is in situ, but 

 the passage between it and the overlying haimantas is so gradual that 

 a boundary line can only be drawn diagramatically. The mineralogical 

 character of the shales and quartzites lying below the typical purple 

 quartzites (2) with the boulder bed (conglomerate), and the adjoining 

 metamorphic schists (vaikritas), are merging one into the other. The 

 lowest haimantas also contain garnets and mica, the latter in the 

 planes of bedding and irregular layers and crystals (in the plane of 

 bedding) of felspar become frequent high up the series. Beds of 

 granite (albite) intrusions, and syenitic granite, are found all through- 

 out the lower haimanta system, their veins and complicated intrusions 

 shewing distinctly in the darker coloured rock. South of Milam 

 village one enters into the region of the great central flexure of 

 gneissose rocks with the overlying older metamorphic schists. 



Eastern Johar and Dharma. 



What I said about the indistinct boundary of the vaikritas with 



TT . the haimantas in the Milam sections may be 



Haimanta boundary. 



applied also to the ground lying south-east of it 



as far as the Nepali frontier. I could actually follow the boundary 

 only in two sections in this far extended area, namely, in Eastern 

 JohaV between the village of Chail on the Dharma (Dhauli) Ganga, 

 and the junction of the latter with the Lissar river, where the haimanta 

 rocks are overlaid by the silurian system, and in Byans, along the sec- 

 tion exposed by the Kali river. The actual boundary of the haimanta 

 system near its base is so obscure, and the passage from the meta- 



( 159 ) 



