Wheelton hind in his Monograph on Carbonicola gave a critical review of what was known about hinge structure in that genus up to 1896; he described and figured the hinge structure in various species of Carbonicola, notably in shells which he referred to C. acuta (Sowerby). Since that time little has been published about hinge structure in Carbonicola. A paper by M. C. March on the structure and relationships of Carbonicola appears only to have been published in abstract (1913): In that, mention was made of the specialization of the ligament and “cardinal plateau” in the hinge line of Carbonicola, the “cardinal plateau” being grooved for the reception of an internal ligament. It was also stated that hinge structure was absent in C. antiqua, poorly represented in C. turgida and similar forms, and most highly developed in C. aquilina.

The great volume of extrusive rocks which has accumulated during and since the Tertiary period is one of the most important geological features of East Africa, and one which various people have related to the formation of the Rift Valley System.

The line of demarcation between the Pliocene and the Pleistocene systems is of more importance than would at first sight appear, if for no other reason than because when stratigraphers and palaeontologists are forced by one consideration or another to use the system in preference to the stage names it is often impossible to gather the actual age which they attribute to the deposit or fauna which they are describing. This paper aims at explaining my own point of view, by which I hope to incline adverse scientific opinion towards a definite predilection for the division which I myself favour. Perhaps this may eventually lead to a pronouncement on the question by an authoritative international committee.

Although there are in existence numberless books, many of them of great excellence, dealing with the effects of denudation (Geomorphology) nevertheless long experience and much reading seem to show that the more descriptive side of the subject, the result of the processes, has received more attention than the actual mechanism by which the results have been brought about. This applies more particularly to river erosion. In most books there is at the outset a tacit assumption that rivers do erode and the matter is left at that. Now rivers and running water generally certainly do perform the work of denudation somehow, as is proved beyond doubt by the large amount of material sometimes carried in suspension. But a careful consideration seems to show that the subject is not quite so simple as would appear from most textbooks.

The Shunner Fell Limestone is one of a group of calcareous shales and impure limestones, in all about fifteen feet thick, occurring in beds of Namurian age and Millstone Grit facies exposed on Shunner Fell, Wensleydale. The presence of Anthracoceras glabrum s.l. Bisat in these beds (Chubb and Hudson, 1925, p. 262) assigns them to the Arnsbergian (Upper Eumorphoceras Age, E2, Hudson and Cotton, 1943). Other fossils include small cornute corals, trilobites, gastropods such as Bellerophon and Euphemus, and brachiopods such as Athyris, Chonetes, Lingula, Schizophoria, Spirfer, and the spinose Productids. The occurrence of these beds and some of their fossils has been recorded by Goodchild (in Dakyns and others, 1891, p. 145), King (1914), and Chubb and Hudson (1925).