all quite distinct from Damúda forms. These beds were first accurately described by Professor Oldham in a paper published in the Society’s Journal for the year 1853. They have since been named by him the Rájmahál series. It was, however, at first thought that a slight passage existed between the Damúda and Rájmahál groups, a view which Professor Oldham has since announced to be erroneous; the passage, if any exists, occurring in the conglomerates and grits interposed between the two series. Memoirs of Geological Survey of India, Vol. II. pp. 313, 325.
The conglomerates and grits of Panchit hill, provisionally termed the Upper Panchits, agree perfectly in mineral characters with those underlying the traps in the Rájmahál hills. As there is every probability that they occupy the same position in the general series, it is not unreasonable to suppose that they are an extension of the same beds.
A still higher group occurs in Orissa and in Central India, to which the name of Máhádeva has been given. No representatives of it are known in Bengal, and it is possibly considerably higher in the series than any of the groups above mentioned.[1] It is not by any
- ↑ Professor Oldham has suggested as probable that it is of Nummulitic (Middle Eocene) age. (Mem. of the Geological Survey of India, Vol. I. p. 171 and Vol. II. p. 210 note), and there are doubtless arguments in favor of his suggestion. But the Máhádevas are in Central India overlaid unconformably by an intertrappean series abounding in a shell, Physa Prinsepii, said to be very closely allied to Physa Nummulitica of D’Archiac from the Nummulitic rocks of the Panjáb, if not identical with it. (See Hislop on the Tertiary beds and fossils of Nagpur, Quarterly Journal, Geological Society, Vol. XVI. pp. 163, 164). By D’Orbigny (Prodrome de Paléontologie, II. 299) Physa Prinsepii was considered identical with P. Gigantea, Du Boissy, from beds near Rheims which are of the lowest Eocene age, even below the plastic clay, while Nummulitic rocks are considered by the best authors on the subject, as, at lowest, middle Eocene. There is much general similarity of facies between the fresh water (? land) shells of the Rheims beds (Mem. de la Societé Geologique de France 2e. serie, Tome II. plate 6) and those of the intertrappeans of Central India. The identifications of the Physas are dubious, especially that of D’Orbigny, but the resemblance of the facies is important. So far as this evidence goes, it tends to point out the intertrappean beds as at least as low in the series as the Nummulitics and possibly lower. In this event, from the great break between the intertrappeans and the Mahadevas the latter must, a fortiori, be of pre-Nutnmulitic date. But all the evidence either way is of an extremely slight description.
