The Imperial Gazetteer of Indiaoccu. The associated rocks are all sandstones and shales,

which sometimes attain a thickness of 10,000 feet The ironstone shale stage is so called on account of the lenses of clay ironstone which, as in the Ranlganj coalfield, sometimes occur in sufficient abundance to supply a valuable iron-ore. All these stages are in general conformity with one another, though the upper may be found to overlap the lower.

There is generally, however, a slight unconformity between the uppermost stage of the Damuda series and the next, which is distinguished as the Panchet series. The Panchets are characterized by the absence of coal-seams, being composed of micaceous sandstones, often of a greenish colour, with bands of red clay. The series is well-known on account of the reptilian and amphibian fossil bones it has yielded, besides a few fossil plants which show more pronounced affinities with reptilian

Damudas than with the higher beds. The whole of the foregoing series Talcher, Damuda, and Pflnchet make up the lower division of the Gondwana system, being cut off from the Upper Gondwanas by a marked strati-

those of the

graphical break, accompanied by a contrast in fossil contents. The plants of the Lower Gondwana beds include many equi-

setaceous forms, while those of the

Upper Gondwanas show

a prevalence of cycads and conifers ; the species of common genera of ferns, as well as other orders, are quite distinct in the

two

divisions.

The Upper Gondwanas have

a lower series, distinguished as Uppei the Rajmahal series in Bengal and as the Mahadevas in the Gondwanas. The Mahadevas attain a thickcentral parts of the Peninsula. ness of 10,000 feet in the Satpura area, most of the rocks being sandstones and unfossiliferous. The Rajmahals, on the other

hand, have yielded a number of fossil plants, and are interesting, too, on account of the great sheets of basaltic lava

and sandy sediments, attaining thickness of over 2,000 feet. The Rajmahal lava-flows are a often amygdaloidal like those of the Deccan trap series, the

, ,. , cavities yielding agates and zeolites of considerable variety interstratified with the shaly

...,,.

,.

and beauty. Rocks of Upper Gondwana age occur along the east coast of

tlte

Peninsula.

.

,

,

Rajmahal nd Ma la " 5 deva

!

series.

at various places Marine eds f

In some cases marine

u

e

been found associated with the plant-bearing Gondwana and these have helped to fix the position of the Upper a s e beds, Gondwanas in the standard scale of marine strata. More fossils

have

-

pronounced evidence as to the age of the upper limit of the Gondwanas is afforded by the occurrence of plant-bearing G a