TAUT 1.] 
Medlico/t: Geology of North- West Provinces. 
17 
now more worked than any others in India. The gem is, of course, found in the diluvial 
deposits; but the diggings most prized are in the Riwah group of the Vindhyan series. 
Although, however, this group has a very wide range, diamonds are not known to occur 
in it beyond a very limited tract in the State of Pannah. This fact and other observations 
have suggested that the diamond was not originally formed in the Riwah group ; but rather 
in some peculiar contact-rocks at the base of the lower Vindhyan, or Son, series, and well 
exposed in the sections close to the north of Pannah. 
Its distribution .—The Karamnasa, forming the eastern boundary of the North-Western 
Provinces, flows from the eastern extremity of the Vindhyan plateau. Prom here to 
Futehpur Sikri (which stands upon a ridge of Blianrer sandstone), south of Agra, the north 
scarp of the Vindhyans corresponds approximately with the south boundary of the 
provinces; the native states of lower Bandelkund being intricately interwoven with the 
districts of Banda, Lalatpur, and Jhansi. Only, on the east, the Mirzapur district stretches 
southward across the Vindhyan plateau, here formed of tho Kaimur group, and across the 
S6n valley, where there is a full section of the lower Vindhyan, or S6n, series. Tho 
northern outcrop of this same series is exposed in the Banda district, about Ifirwi. Tho 
Gwalior series just touches the border of the province in the Etawah district. 
The slate series .—In discussing the range of the Vindhyan series, the Bijawar 
formation was mentioned as showing incipient metamorphic action. It is made up of 
hornstone-breceias, quartzite-sandstone, cherty limestones, ferruginous sub-schistose slaty 
shales, and thick sheets of basic trap-rock. The districts of Bauda and Lalatpur just touch 
upon the original area of these rocks in Bijawar. In tho Mirzapur district, in the hills 
south of the Son, similar rocks occur, in a state of high contortion, and connected on the 
south with a broad band of clay-slates, which are in turn intimately associated with 
crystalline schists and gneiss. 
The schist and gneiss series .—The wide bay formed by the Vindhyan scarp between 
Gwalior on the north-west and Kirwi on the south-east is occupied by highly metamorphic 
rocks,—coarse porphyritoid gneiss and crystalline schists. In the districts of .Hums and 
Lalatpur these rocks appear freely ; but to tho north-east, in the districts of Jaloun, Hamirpur, 
and Banda, outcrops become more and more scarce as the rock disappears under the 
plains deposits. The strike of the foliation and of the bedding, where observable, is 
generally east and west. Greenstone dykes are very abundant, with a prevailing north-west- 
south-east direction. None of these dykes pass into any of the overlying sedimentary rocks, 
and are therefore presumably of older date. The most striking feature of this area is 
the prevalence of great quartz-reefs, standing up in great wall-like ridges, sometimes 
more than threo hundred feet high, many yards wide, and running quite straight for 
several miles continuously, or with intervals appearing again on the same strike. They 
have a prevailing north-easterly run, but exceptions are frequent. These also are certainly 
older than the Bijawar formation, and also apparently older than the trap dykes. It has 
been thought that gold should be found in or about these great quartz-reefs ; but there is 
no trace or tradition of its occurrence. According to some theories, this would be accounted 
for by the extreme antiquity of these reefs and of the enclosing gneiss. 
The gneiss at the southern point of tho Mirzapur district in Singrowli belongs to the 
great metamorphic area of Bchar and Bengal. Here also massive porphyritic and granitoid 
gneiss is the predominant rock, with subordinate bands of hornblende schist. There is a 
strong hand of fine Corundum in it near the village of Pipra. Bands of crystalline 
dolomite and limestone are also frequent in this gneiss; whereas none whatever has been 
observed in the gneiss of Bandelkund. 
H. B. MEDLICOTT. 
September 1872, 
