Societies and Academies

Abstract

Geological Society, June 21.—Joseph Prestwich, F.R.S., in the chair.—R. J. Watson, W. T. Scarth, Gen. A. C. Bentinck, and John Brooke were elected Fellows of the Society.—“On some supposed Vegetable Fossils,”by William Carruthers, F. R.S. In this paper the author desired to record certain examples of objects which had been regarded, erroneously, as vegetable fossils. The specimens to which he specially alluded were as follows:“Supposed fruits on which Geinitz founded the genus Guilielmites, namely, Carpolites umbonatus Sternb., and Guilielmites permianus Gein., which the author regarded as the result of the presence of fluid or gaseous matter in the rock when in a plastic state; some roundish bodies, which, when occurring in the Stonesfield slate, have been regarded as fossil fruits, but which the author considered to be the ova of reptiles, and of which he described two new forms; and the flat, horny pen of a Cuttlefish from the Purbeck oi Dorsetshire, described by th author as Tendopsis Brodiei, sp. n. Mr. Seeley remarked on the compressed spheroids found in so many rocks, that there was a difficulty in accepting the view of their originating in fluid vesicles, though he was unable to suggest any other theory by which to account for them. He observed that the eggs from the Stone field slate closely resemble those of birds, and that it was of the highest interest to find such eggs in strata containing so many remains of ornithosaurian forms, such as Rhamphorhynchus and Pterodactylus, of which genus probably these were the eggs. Prof. Rupert Jones fully recognised the ingenious explanation of the bubble-formed limited slickensides, that looked so much like possible fossil fruits, and Mr. Carruthers's masterly treatment of the other specimens. But he wished that the author would take up the subject exhaustively, and define the nature of other supposed vegetable fossils, such as the so-called fucoids, Palæochorda, Palæopkyton, Oldftamia, &c, many, if not all, of which Prof. Jones thought to be due to galleries and other tracks made by Crustaceans. Prof. Ramsay had known many instances of such blunders as those pointed out, made, not by experienced geologists, but by those unacquainted with the science. Though he had never regarded the flattened spheroids as fossils, he was unable to account for their presence in the clay-beds of different ages. Mr. Hulke inquired whether Mr. Carruthers considered the limited slickensides common in the Kimmeridge shales as due to gaseous origin. He remarked on the rarity of Ptero-dactylian remains as compared with those of other Saurians in the Wealden beds, in which the presumed eggs of Pterodactyls were found. Mr. Seeley did not regard the Wealden egg as being that of a Pterodactyle. Mr. Carruthers, in reply, remarked that the local slickensides mentioned by Mr. Hulke differed in character from those to which he had referred.—“Notes on the Geology of part of the County of Donegal,” by A. H. Green, F.G.S. In this paper the author described the geological structure of the country in the neighbourhood of the Errigal Mountain, with the view of demonstrating the occurrence in this district of an inter-stratification with mica-schist of beds of rock, which can hardly be distinguished from granite, the very gradual passage from alternations of granitic gneiss and mica-schist into granite alone, and the marked traces of bedding and other signs of stratification that appear in the granite, to which the author ascribed a metamorphic origin. He also noticed the marks of ice-action observed by him in this region, and referred especially to some remarkable fluted bosses of quartzite, and to the formation of some small lakes by the scooping action of ice. Mr. Forbes stated that none of the facts of this communication were new, but he dissented altogether from the conclusions arrived at by the author in regarding these rocks as originally of sedimentary origin, and for the following reasons: (I) That this district has been studied in detail by Mr. Scott and Prof. Haughton, who declare the rock to be undoubtedly intrusive, as it not only sends out veins into the neighbouring strata, but also encloses fragments of the rocks through which it has broken. (2) Because the author starts from the idea that if such rocks are found to lie conformably on beds of undoubted sedimentary origin, it is a proof of their being themselves sedimentary or stratified,—a conclus on which is totally unwarranted, since there are innumerable instances, not only of beds of lava or other igneous rocks being conformable to fossiliferous strata, but of their also being found intercalared with such beds even for considerable distances. (3) The stra a, so far from being proved by him to be of truly sedimentary origin, arc of a most questionable origin, since they are neiiher in themselves fossiliferous, nor can they be correlated with any containing fossils as proofs of true sedimentary deposition; and the description of his section is sufficient to show this; for although it looks well on paper on a scale of three feet to the mile, the author has so little confidence in it that he is not evert certain as to which is the top or bottom of the section on which so much generalisation is based. (4)