60 Records of the Geolvyical &urcey of India. [voL. xil. 
The white limestones at Hango are, I apprehend, the same rocks as the pink 
limestones on the south side of the pass. 
Tnrthcr on, at a point where the road, having rounded a spur, winds into 
the mountain side, slates re-appcarcd dipping west. As the silicious limestones 
did not crop out between the blue limestones and the slates, I presume they were 
hidden by the talus, which, at the level of the road, is very abundant along 
this section. As the crystalline series Avas neared I came to a pale bluish-white 
slate weathering a bright yclloAvish ochre color in irregular patches. Associated 
with the latter was a thin bed of dark slate, in some places as black as coal. 
From these rocks I passed by a sudden transition to the crystalline series. 
The change takes place just W'here the road from Hango rounds the edge of 
the Tinga ridge, at an elevation of 11,500 feet, before the commencement of the 
descent to Leo. The slates rest up)on the crystalline rocks, and no material 
change of di^ rvould he observed in passing from the one series to the other. 
The crystalline series extends from the point indicated up to (and probably 
beyond) the Para river, but at and beyond Change, as will be shoAvn further on, 
they are OA'erlapped bj^ pink limestones and calcareous slates. The lowest beds 
in the crystalline series at Leo are massive quartzites; these are followed by 
thin-bedded white and bluish-Avhite qitartzitos, with some beds of mica schists. 
Higher up in the series the mica schists become more prominent. Some of the 
latter are fine-grained silicious rocks, shotving no mica on the Aveathered surface. 
The crystalline rocks, quite up to their junction wdth the unaltered rocks, 
are riddled through and through by dykes and veins of albite granite, varying 
in thickness from about 30 feet to the fraction of an inch. The granite is 
undoubtedly intrusive. It may be seen throughout the crystalline series betAA’cen 
Leo and Chango, from the bed of the Spiti river up to the tops of the highest 
peaks, profusely penetrating the strata in all directions ; sometimes darting across 
them in long zigzags, like forked lightning; at others, folloAving the line of 
bedding for some distance, and then either dwindling aAA'ay into thin strings, or 
terminating suddenly to burst out in adjacent strata Avdth redoubled force. 
The granite in the gneiss in the vicinity of Chango has already been 
identified as albite granite (Memoirs, vol. V, p. 154). It presents all the 
characteristics of the intrusive albite granite of the Wangtu section of- the 
Sutlej Amlley, being a mixture of quartz, muscovite, schorl, and a snoAv-Avhite 
felspar {occasionally shoAA'ing triclinic striations) that scarcely Aveathers at all. 
When the schorl is sparsely scattered through the rock, the muscovite is plentiful 
and in good sized packets or leaves, but Avhen the black tourmaline is abundant, 
the muscovite becomes A'cry subordinate and dwindles to thin flakes of small size. 
In some places the schorl is profusely scattered through the rock, in irregularly 
shaped fragments. 
Hoar Chango I found cj'anite in mica schists. It was of beautiful cobalt 
blue, shading into a pearly Avhite, but the blades Avere not nearly so large as those 
of the mineral found in the central gneiss near Wangtu. In the same locality 
Ihcre AA'cre some chiastolite schists near granite. 
