16 
Records of the Geological Survey of India. 
[vol. VI. 
not yet been fixed. The rooks to which the name was first given, or rather adopted from 
the old geographical name, are the strong fine sandstones forming a very long range of cliffs 
along the north side of the Narbada valley from Hosungabad to Jabalpur, and continuous 
thence along the north of the Son valley to Sasseram in Behar. As the sandstones recede 
from this line of cliffs, they become steadily split up by thick bands of shales, with lime¬ 
stones, and so necessitating a division into three principal groups, as Bhanrer, Riwah, and 
Kaimur, forming the original Vindhyan series. In the Son valley the sandstone cliff’is 
weathered back to the north of its line in the Narbada country; thus exposing older beds, 
underlying the Kaimur sandstone. These consist of limestones, fine flaggy sandstones and 
shales, with strong bands of very peculiar porcellanic and trappoid beds; the whole forming 
a series of local groups. Beds of exactly the same description as those of the Son 
Valley appear again along the north edge of the Vindhyan basin; and here also they 
stop out against the gneissic rocks of lower Bandelkand, and so are entirely over¬ 
lapped by the Kaimur sandstone. They were here first described as the Semri series, 
but are now properly merged in the Son series. As these strata present throughout 
steady parallelism with the Vindhyan beds above them, both occupying the same basin, 
being alike affected by local disturbance, and alike free from any symptoms of meta¬ 
morphism (except the conversion of the sandstone into quartzite in certain positions 
of disturbance), the name Vindhyan has been extended to the whole series, with only 
the distinction of Upper for all the original Vindhyans and of Lower for the Son 
series. On the north side of the gneissic area of lower Bandelkand, about Gwalior, there 
is a group of rocks resting, just as the upper Vindhyans themselves do, upon an old surface 
of the gneiss; they have scarcely undergone any more disturbance or metamorphism than 
the Vindhyans; but the Kaimur conglomerate rests unconformably upon an ancient surface 
of erosion of these rocks, and is largely made up of their debris. There is, however, 
at least one marked character common to the Gwaliors and the lower Vindhyans—the 
peculiar porcellanic and porphyritoid beds occur in both; and it would be by no means 
improbable to suppose that the two are in part cotemporaneous deposits. There are 
also marked differences between them; the Gwaliors are highly ferruginous and include 
some strong sheets of cotemporaneous basic trap. These new characters, on the other 
hand, suggest another link in the descending series of formations: recrossing the same 
gneiss, to the south, we find in the Bijawar country a new group of rocks, still again 
resting flatly upon an eroded surface of the gneiss, only partially disturbed and showing only 
incipient metamorphism, but upon which the original lower Vindhjrans rest unconformably. 
Cotemporaneous trap and highly ferruginous deposits are marked features of this Bijawar 
group; and it would not be extravagant to assume that it is, in part, cotemporaneous with 
the Gwalior group. Again, in the S6n Valley, the lower Vindhyans rest with extreme 
unconformity upon beds that have been thought to represent those of Bijawar, and which 
have become highly metamorphia and associated with gneissic rocks. We thus finally arrive 
at the suggestion of a younger and an older gneissic series; without fluffing, below the 
Vindhyans proper, a clearly marked physical break applicable generally over even so small a 
geological field as the Indian Peninsula. 
The stratigraphical difficulties observed in the preceding paragraph might be removed 
by the aid of fossils; but to the great disappointment of geologists in India, the Vindhyans 
have as yet yielded no organic remains, although the undisturbed and unaltered strata 
composing them, often covered with fine ripple marking, continually tempt one with the 
hope of successful search. Some forms supposed to be corals were found by Mr. Hacket in 
a limestone of the Gwalior series. 
Besides producing in abundance building stone of first rate quality and limestone, 
the Vindhyans are only remarkable as containing diamonds. The mines near Pannah are 
