PART 1.] 
Mallet: Qeological Notes. 
39 
The section across the G h a g r a valley is a synclinal, the hand of quartzite north of 
Gawan being clearly the same as that at Nurpani. It turns round again in sheet 2 
(as observed by Mr. Willson), and re-enters sheet 8, near Gawan, where it again bends round 
sharply to south-east. It is here interbanded with hornblende- and mica-schists, the section 
in this respect resembling that of the B h i a u r a range. 
There appears to be another synclinal in the S a k r i valley below B i r n e, the 
quartzites on both sides being, I believe, the same ; that ou the left, however, is softer and 
more micaceous, much of it, in fact, verging towards a micaceous quartz schist, and passing 
insensibly into the mica-schist below. The same rook much mixed with mica-schist, and even 
gneissose beds, is found again north-east of P i h r a, the boundary between it and the 
metamorphics being a faulted one, indicated along the greater portion of its length by a line 
of hornstone. 
Further south still, the mica-schists are most commonly, but not always, found in direct 
contact with the gneiss. The rock in the neighbourhood of Bajpura is of a very inde¬ 
finite character, every gradation from quartzite to mica-schist being found, but too much 
mixed up to admit of separation. In the western part of the sheet, as I have previously 
pointed out, the quartzite makes its appearance again, but in the Ratanpur area the 
schists are the contact rocks, there being here, as elsewhere, a passage, sometimes gradual, 
sometimes tolerably sharp, into the gneiss. North-west of the above-mentioned village the 
mica-schist contains abundance of staurolite. 
In Mahabar Hill we have the highest member of the series present in this part 
of the country: a great thickness of quartzite overlying the mica-schists. At the mouth 
of the Mangraun gorge the junction of the two rocks is well seen, there being a complete 
passage from one to the other in about 20 yards; half-way between thin layers of both 
are interstratified. The quartzite forms a great synclinal, dipping everywhere (at the ends 
of the hill as well as on the flanks) into the hill at angles mostly from 30° to 80°. In the 
central part of the range the rock is so crushed, that the bedding is sometimes quite obscured. 
In some cases also, planes of what appear to be cleavage, are visible, having a direction differ¬ 
ent from that of the bedding. This peculiar trough-like conformation, and the high in¬ 
clination of the strata, is remarkably favorable to the retention of water, and the volume 
flowing from the densely forest-clad gorges which wind in amongst the hills, strikes one as 
exceptionally great. 
The absence in the P a t r u valley of the large thickness of mica-scliists, which is 
present immediately to the south-west, must, I believe, be attributed to a fault with northern 
downthrow. The junction of the quartzite with the schists however, and of the latter with 
the gneiss, is natural, so that the fault must occur in the schists themselves. It is apparently 
by another fault running north and south with western downthrow, that the quartzite is 
brought almost in contact with the gneiss in the valley north of K o t i y a r. 
According to the above view, it will he seen that in Northern Hazaribagh the sub- 
metamorphics include three main subordinate groups, viz .:— 
Mahabar quartzite. 
Mica-schists, including subordinate bands of arenaceous and hornblendic schists. 
JBhiaura quartzite, sometimes wanting, in other places attaining a great thickness, 
and sometimes interbanded with hornblende- and mica-sebists. 
Pegmatite granite. —Through both gneiss and submotamorphics, but especially in the 
latter, there is a large development of pegmatitic granite,* penetrating the older rocks in 
* In most English standard works on geology pegmatite Is defined as consisting essentially of quartz and 
felspar, with little or no mica; and in some, as identical with graphic granite. Delesse, however, and Naumann 
describe it as a very coarse mixture of quartz, felspar, and silvery mica, often containing tourmaline. It is in the 
iatter sense that the word is used here. 
