Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/126

 The following communications were read : —

1. On some points of South- African Geology. — Part I.

By G. W. Stow, Esq.*

(Communicated by Prof. T. Rupert Jones, F.G.S.)

[Abstract.]

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 Zwartkop'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 gave 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, characterized by the presence of a large Panopoea. 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 characterizing the Pliocene Limestone.

Discussion.

Mr. J. 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., remarked on the importance, if the conclusions of the author were sustained, of the older post-tertiary beds denoting a warmer climate than the present, instead of, as in the Northern Hemisphere, a colder.


 * The publication of this paper is deferred.