78 Revieics — D. W. Freah field — Round Kanchenjunga. 



partly from observations in situ. No one, we presume, has hitherto 

 ch:)sely approached the actual throne of the monarch, which probably 

 consists of fine white or grey granite in a setting of augen-gneiss, 

 which latter is by far the most abundant rock variety throughout 

 the immediate vicinity of this mountain mass. Of actual granite 

 the indications are by no means numerous. During the descent 

 of the Jonsong glacier the party had good opportunities for observing 

 the northern precipices of Kanchenjunga. " In their lower portion, 

 at all events, they appear to be formed of massive augen-gneiss 

 })enetrated by pegmatites, these being the only rocks found on the 

 moraines of the Kanchenjunga glacier. Sometimes the gneiss is 

 finer and contains hornblende, but this mineral is absent from the 

 Kanchenjunga gneiss, and it is probable that the hornblende-bearing 

 variety belongs to a different rock into which the augen-gneiss is 

 intruded. This gneiss forms the cliffs of the Kangbachen and 

 Khunza valleys, and is recorded by Hooker as occurring also further 

 west in the Yangina valley as far north as he penetrated. The same 

 rocks again appear to form the massive walls of Jannu, and to 

 stretch south-east to Kabru and the Guicha La." This class of rock 

 Professor Garwood regards as a foliated granite intrusion. Its 

 composition is simple, consisting almost entirely of porphyritic eyes 

 of white orthoclase embedded in a foliated matrix of biotite, quartz, 

 and plagioclase felspar. Crystals of tourmaline, hornblende, and 

 garnet are invariably absent from the typical augen rock, but are 

 plentiful in the pegmatites associated with it. 



There remains one more subject for consideration with reference 

 to the geology of this region, viz. the absence of specifically recog- 

 nizable fossils, although there are evidences of altered limestones 

 in connection with the gneissic masses. Three distinct and widely 

 separated localities ai'e marked on the geological map as follows : — 



(1) In the far north-east, near the Donkhya Pass and Cholamo 

 Lake, where Hooker observed ■' fossil limestone, much foliated and 

 faulted ; blue pisolitic conglomerate ; shale and iron pyrites, some 

 crystalline with encrinites, and (?) nummulites too altered for 

 determination." This is at an elevation of over 18,000 feet on the 

 borders of Thibet. 



(2) Still on the Thibetan frontier, near the Chortenima La, which 

 has an elevation of 18,650 feet, and only a little to the north of 

 the track to the Jonsong Pass, ai'e "altered limestones with Crinoid 

 stems ; sandstone altered into quartzites, and tourmaline-calcite 

 rocks." One might be inclined to believe that these are limestones 

 of Carboniferous age which have undergone alteration from contact 

 with an igneous mass. Supposing them to be Carboniferous and 

 not Eocene limestones, their presence has no particular bearing 

 on the age of this part of the Himalayan uplift, though there is no 

 reason to suppose that such uplift is otherwise than Tertiary in date. 



(3) On the western slopes of Pandim (22,020 feet) we find 

 indicated on the map " metamorphic sedimentary rock, with 

 intrusive pegmatites and hornblende gneiss." These appearances 

 had already been described by Hooker from a distance as looking 



