Reviews — C. L. GrieabacKs Central Himalayas. 269 



the nortli-west as far as the Sutlej gorge. Within this area the 

 Central Himalayas may be divided into a Northern range, in which 

 is the water-shed of the region, and a Southern range which contains 

 the highest peaks. This latter is mainly formed of crystalline rocks, 

 chiefly gneisses and metamorphic schists, whilst the Northern range 

 is almost entirely composed of a vast thickness of sedimentary 

 strata ranging from the lowest Paleozoic to late Tertiary. This 

 memoir mainly relates to the cliaracter of these sedimentary deposits, 

 which are now elevated so as to form a high rim round the southern 

 edge of the great high plateau of Hundes, which in its lowest portion 

 is 12,000 to 16,000 feet above sea-level. The principal geological 

 features of this region have already been made known in the works 

 of General Strachey and Dr. F. Stoliczka ; the present report, which 

 is the result of nearly twelve years' investigation, very materially 

 adds to our knowledge of its geological structure, and in some 

 respects considei'ably modifies the descriptions of the earlier writers. 



The region under consideration is indeed a wild one ; a large part 

 of it is above the line of perpetual snow, which in the Southern 

 range is between 15,000 and 16,000 feet above the sea, and in 

 the Northern somewhat higher. Nearly every valley above these 

 elevations has its glacier, and some of these range from five to 

 sixteen miles in length. A fact, interesting to glacial geologists, is 

 noted by the author, viz. that during years of observation he failed 

 to find striated and polished boulders in the moraines of these 

 glaciers, whilst the bounding rock-walls of the glacier-valleys do 

 not show the smooth and rounded surfaces, usuallj'- seen in other 

 regions, and it is supposed that subaerial denudation and rapid 

 weathering has obliterated the ice-markings. From the presence 

 of morainic material at lower levels, the author concludes that the 

 glaciers must formerljr have extended much further than at present. 

 In one respect the geologist has an advantage in these high mountain 

 regions, for the rocks are not hidden by vegetation, and in the absence 

 of snow the main stratigraphical features can be noted readily even 

 from a distance. 



The main mass of the Himalayas consists of an enormous thick- 

 ness of crystalline rocks, in which two systems can be recognized ; 

 an older of granitic gneiss, which is now known to be metamoi-phio 

 granite ; and a younger series of micaceous schists, talcose rocks, 

 phyllites and gneiss, to which the name of "Vaikrita" system is 

 applied. Both the lower gneiss and Vaikrita systems are inter- 

 penetrated by veins and masses of eruptive granite, which also 

 traverse the next overlying Haimanta rocks. 



The lowest distinctly sedimentary rocks, which rest, without any 

 clear line of division, on the Vaikrita schists and gneiss, consist at 

 their base of thick beds of conglomerate and purple quartzites, suc- 

 ceeded by shales and phyllites, and limited above by a zone of bright 

 red quartz shales, with an estimated thickness altogether of 4000 

 feet. This series, named the " Haimanta " system, is probably the 

 equivalent of the Cambrian and older divisions, and may correspond 

 with Strachey's azoic slates. The only organisms yet found in them 

 are traces of Grinoid-stems, casts of bivalves and of Bellerophoiu 



