Page:Journal of the Asiatic Society of Bengal Vol 29.djvu/388

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358

On the rocks of the Damúda group.

[No. 4.

means certain that the beds of Orissa and Central India are of the same age.

The age of the rocks associated with the coal of Bengal is still undecided, but it is to be hoped that the examination of the reptilian remains from the Panchit beds may throw some light upon the question. The occurrence of the little Æstheria, a crustacean singularly abundant in the Trias of England and Germany, the coal field (Lower Mesozoic and probably Triassic) of Richmond, Virginia, U. S., and in Nagpúr in connexion with a reptile belonging to a group peculiar to the Trassic and Permian periods, (Rupert Jones on Æstheria Minuta, Quarterly Journal, Geological Society, XII.) seems to add weight to the gradually accumulating evidence in favor of these beds being classed with the still imperfectly known groups which are considered by European geologists to form the close of the Paleozoic and the commencement of the Mesozoic epochs. (See Professor Oldham’s paper on the geological relations and probable geological age of the several systems of rocks in Central India and Bengal. Mem. Geological Survey of India, Vol. II. p. 295.)

There are three localities whence more accurate determination of the age of these rocks may be expected. Of these one is in Australia, the other two in India, on the banks of the Godavery, S. of Nagpur and in Cutch; and the attention of all interested on the Geology of India should be directed to the desirability of obtaining all possible accurate information from these places.

The following diagram represents the views above put forward of the relations of the different series referred to together with their distribution throughout Eastern and Central India.

Rániganj.

Rájmahál.

Orissa.

Nurbadda valley.

Nagpúr.

1.

Rániganj„

Rájmahál„

Máhádevas?

Máhádevas. Lametas.

Máhádevas.

2.