Abstract
LONDON Geological Society, November 23.—Mr. Joseph Prestwich, F.R.S., president, in the chair.—1. “On some points of South-African Geology.” Part 1.—By Mr. G. W. Stow. In this paper, which was illustrated by numerous sketches, sections, tables, and specimens, observations were made on the stratification of the Jurassic beds of Sunday's and Zwarktop's rivers, resulting from researches made by Mr. Stow, with the view of determining the exact position of the several species of fossils found at the exposures on the cliffs of these rivers, and from this the sequence of the various beds. He indicated the existence of at least nine separate fossiliferous bands, pointing out the relative positions of the several Trigonia-beds, Hamite-beds, Ammonite-beds, &c. He next treated of the so-called Saliferous beds of the district, and gives his reasons for regarding them as later in age than the Trigonia-sandstones above alluded to, and therefore not equivalent to that part of the series named “Wood-beds” by Dr. Atherstone. Other researches of the author related to the Tertiary beds both inland and on the coast. He distinguished three zones on the coast later in date than the high-level shell limestones (Pliocene?) of the Grass Ridge and other parts of the interior. One of the coast-zones he named the Akera-bed, from the prevalence of a delicate species of that genus. Another zone was described as following the river-valleys in the form of raised terraces, characterised by the presence of a large Panopcæ, The latest shell-banks have been thought to be kitchen-middens, but the author regarded them as shore-deposits in place. The author concluded by tracing the probable climatal and geographical changes in this region during geological times, and indicated, as far as his material allowed, the probable migrations of the Mollusca, especially of the Venericardia characterising the Pliocene Limestone. Mr. Gwyn Jeffreys remarked that all the shells belonging to the genus Akera which he had examined were shallow water or littoral shells. Dr. Duncan remarked on one of the corals as being of a well-known Crag form, the Balanophyllia calyculus. Mr. Searles Wood, jun., observed that there appeared some probability on the face of the paper of the shells of the older post-tertiary beds denoting a warmer climate than the present, instead of, as here, a colder.— 2. “Note on some Reptilian Fossils from Gozo.” By Mr. J. W. Hulke, F.R.S., F.G.S. The author described the remains of two reptiles said to have been brought from Gozo by the late Captain Strickland. One of them was a fragment of the symphysial part of the slender mandible of an Ichthyosaurus, having teeth of precisely the same character as those of the form from the Kimmeridge Clay described by the author under the name of Enthekiodon. For this species the name of Ichthyosaurus gaudensis was proposed. The other was the skull of a species of crocodile, for which the author proposed the name C. gaudeiisis. Dr. Duncan suggested that the Ichthyosaurian fossil might be derivative from some secondary rock. He mentioned that Dr. Leith Adams had once sent him an Aspidiscus cristatus from the Hippurite Limestone, which was stated to have come from Malta. To account for this, he suggested that the Miocene of Malta might have been supported on beds of Cretaceous age, so fossils from that source might have become indebted in the coral reefs of the later date. Capt. Spratt expressed a doubt of the fossils having really come from Gozo. He did not recognise the cretaceous-looking matrix among any of the rocks of that island, with all of which he was acquainted. The nearest approach to that kind of rock was to be found in the lowest of the deposits near Cairo, which were probably Eocene. Prof.T. Rupert Jones suggested an examination of the Foraminifera in the matrix, with the view of determining its Secondary or Tertiary age. He mentioned the occurrence of rolled nodules of older rocks in beds of later age at Gozo. Mr. Busk stated that a stone of similar character to the matrix occurred in Malta, if not in Gozo, but probably in both. Mr. Hulke, in reply, observed that he had in this paper intentionally left the stratigraphical part of the question untouched, and confined himself to the palæontological aspect of the remains.—3. “On the discovery of a ‘Bone-bed’ in the lowest of the ‘Lynton Grey Beds,’ North Devon.” By F. Royston Fairbank, M.D. In this paper the author called attention to the occurrence of a thin bed of rock to the west of the harbour of Lynmoutb, containing an immense number of fragments of bone, some of them of large size, and associated with massive bodies which he regards as coprolites. The author proposed to call this the “Lynton Bone-bed;” and he thought that its discovery might throw some light on the relative age of the whole series of rocks of North Devon. Mr. Whitaker had examined the beds in company with Mr. Wetherell. He did not agree with the author as to the amount of iron in the beds. The bone-remains appeared to him to be those of Steganodictyum, which had already been found in the lowest of Devonian beds. He was not prepared to accept the nodules described as being undoubtedly coprolites. Mr. Valpy stated that there were at least a dozen beds on different horizons of much the same character as that described along the coast of North Devon, an account of which had already been published at Ilfracombe.
Article PDF
Rights and permissions
About this article
Cite this article
Societies and Academies . Nature 3, 117–120 (1870). https://doi.org/10.1038/003117a0
Issue Date:
DOI: https://doi.org/10.1038/003117a0