Page:Journal of the Asiatic Society of Bengal Vol 29.djvu/383

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1860.]
On the rocks of the Damúda group.
353

two papers by Mr. J. Homfray, one published in the Asiatic Society’s Journal for 1842, the other published in 1847, and reports by Dr. McClelland, on the Kaharbali coal field, and on other portions of the tract of country between the Ganges and the Grand Trunk Road. It is impossible to consider any of these papers as contributions to science, all being extremely inaccurate. Indeed in one case injury has been done, the plates attached to Dr. McClelland’s report, not being true delineations of the fossils they are intended to represent (a result perhaps of the difficulty of obtaining competent draughtsmen and lithographers in Calcutta) have caused erroneous opinions to be entertained in Europe, amongst Paleontologists, concerning the affinities of the plants figured.

Very little light came from Australia. The plants there associated with the coal were examined by Messrs. Morris and McCoy, and the rocks themselves by Clarke and Strzelecki. Unfortunately the last observers adopted different and irreconcileable opinions, the first named stating that the coal-bearing rocks were interstratified with others containing marine shells of carboniferous age, the other that they rested upon the marine beds. The relations of the plants were generally considered to be oolitic.

This last opinion was supported by the discovery in India of cycadaceous plants, as Zamites, Pterophyllum, &c., allied to forms supposed, until recently, to be characteristic of Jurassic and Upper Mesozoic rocks. These Cycads were moreover in places, as in Nagpúr and the Rájmahál hills, found in the neighbourhood of Vertebraria, Glossopteris, and other genera, peculiar to the coal-bearing rocks, and it was supposed that all were found in the same beds.

The examination of the beds of the Rájmahál hills, of Orissa, and of Central India, by the Geological Survey, together with the valuable observations and collections of the Rev. Mr. Hislop at Nagpúr, have, for some years past, been gradually throwing light upon the true relations of the various beds. The re-examination of the Rániganj or Damúda field during the past two years has supplied several important links in the chain of evidence, and the following is an abstract of the views of the writer upon the classification which may be adopted. The details of the survey of the Rániganj field will be published as usual as the memoirs of the Geological Survey.