Mr. David Forbes remarked that the existence of this leaf-bed would formerly have been regarded as affording grounds for belief in the non-igneous origin of basalt. He had, however, made experiments as to the non-conducting-power of clay, and had found that even half an inch of clay was sufficient to protect vegetable forms from destruction by the heat of a mass of slag allowed to flow over them. In the same manner he had found the forms of leaves still preserved under the lava of Vesuvius and other active volcanoes.
Mr. R. H. Scott called attention to the work of Dr. Heer on the specimens brought home from Greenland by Mr. Whymper, among which he had recognized the fruits of various plants which had already been identified by him from the leaves. The connexion between these beds and those of Bovey Tracey, Oeningen, and other Miocene deposits throughout Europe was now proved; and the collections just brought home from Spitzbergen by the Swedish Polar Expedition would throw further light on the subject. No doubt further discoveries would also be made of a similar character in the north of Ireland. He pointed out the similarity between the Irish section and those of Greenland, where vegetable remains were also found interstratified with basalt.
3. Remarks upon the Basalt Dykes of the Mainland of India opposite to the Islands of Bombay and Salsette. By George T. Clark, Esq., F.G.S.
The following remarks are the result of observations made during the years 1845-6-7 upon the trap rocks of a part of the Bombay Presidency. They were laid aside as being, at that time, of no great interest in England, and are slightly alluded to in a letter from the writer to Dean Buckland, not intended for publication, but which was printed in the Quarterly Journal of the Geological Society for January, 1847 [vol. iii. p. 221].
The paper now offered to the Society was written in that year. Some recent remarks by Mr. A. B. Wynne upon the letter to Dr. Buckland induce the writer now to bring it forward. Whatever value it may possess is derived chiefly from the fact that it relates to a district but little known, geologically, and which, from the difficulties of climate and other local circumstances, is less accessible than might be expected from its easy distance from Bombay.
The physical features of Western India are very peculiar. The surface of the peninsula rises very gradually from the Bay of Bengal to an irregular line ranging north and south from twenty to fifty miles from the western coast. At this line the ground, there very high, terminates in an escarpment of from 100 to 1000 feet in depth, and more or less precipitous. The strip of land intervening between this escarpment and the western sea, though of irregular surface, and containing several lofty spurs from the high ground, and some detached ridges, is on the whole not very much above the sea-level.
