Recent work, both published and unpublished, has considerably increased our knowledge of the goniatite succession in the Namurian of western Europe and the various zones and subzones can now be defined more precisely than hitherto. The major divisions of the Namurian of most value are the former “genus zones” each now raised to the status of an age. Names for these divisions were instituted by Bisat (1928), and were redefined by Hudson and Cotton (1943). The various zones and subzones into which the stages are divided are shown on page 2. The zones differ little from those of previous authors: an attempt has been made to give them equal value and, where possible, the zonal indices in any one stage are of the same genus, thus helping to avoid the confusion caused by the choice as zonal indices of forms of different faunal phase. Neither zonal or subzonal indices are constant in their range in their respective divisions—many of them are confined to a faunal band within the subzone, a few extend into a neighbouring division. The following brief notes are based mainly on the faunal succession of the north of England. The published details of the goniatite faunas in Belgium, Holland, Westphalia, and to a certain extent in Silesia show that the succession there is the same. Comparable forms occur elsewhere as in the Pyrenees, North Africa, Novaya Zemlya, Donetz Basin, Indo-China, Siberia, and U.S.A. The boundaries of the Namurian are those decided on at the Heerlen Congress on Carboniferous Stratigraphy (Jongmans and Gothan, 1937).

When describing river terraces in his recently published account of the “Ice Age in West China” Richardson has assumed without question that in a period characterized by climatic oscillation wetter (and generally also colder) episodes result in aggradation and that degradation follows diminished precipitation.

With regard to the relation between climatic oscillation and terrace formation, some ideas that I have collected in the course of studying accelerated (man-made) erosion, may be useful in a geo-morphological setting. Huntington’s principle and the idea I used in my paper “The Ice Age in West China” are not necessarily opposed, if one limits the application of Huntington’s principle to semi-arid regions which are just on the margin of being able to support a vegetative cover. In such regions a further decrease in precipitation, leading to serious reduction in the protection afforded by vegetation, would accelerate erosion on hillsides and steep valley floors, and this in turn would lead to deposition of spoil on more gently sloping valley floors lower down. A further oscillation of the climate, in the direction of increasing rainfall, would restore the vegetative cover, reduce erosion, reduce the load in the rivers, and allow downcutting to continue. But a still further increase in precipitation might be expected to increase erosion of the type associated with landslips and flooded streams and rivers; once more increased load will be swept down from the steeper hills and stream-beds to the lower and gentler slopes of the rivers, where it will be deposited. In other words, one may say that there is a level of precipitation, probably a moderately low one, at which (apart from human interference) there is a close vegetative cover and geological erosion is at a minimum; any appreciable departure from this level of precipitation in either direction will cause increased geological erosion in the upper courses of streams, and hence increased deposition in their lower courses.

The following pages have as their text three Presidential Addresses by Professor H. H. Read. The first, entitled Metamorphism and Igneous Action, was composed for Section C of the British Association at Dundee. The other two entitled Meditations on Granite, Parts I and II, were read to the Geologists’ Association in 1943 and 1944. They will be referred to for brevity’s sake as Dundee and Granite I and II.

Professor M. Amer, Vice-Rector of the Farouk I University, kindly introduced the writer to the interesting Neolithic site at Maadi (1, 4, and 5) and to similar deposits situated further to the south at Tura. The following note records the minerals present in the southern formation, which proved to be derived from the same sources as those contributing material to the recent Nile deposits at its present bank east of Tura. The investigation showed also that the relative amounts of suspended matter carried by various tributaries of ancient rivers could be determined by examining the relative abundance of the heavy minerals along their courses.

Much has been written on the subject of the physical and climatal conditions under which the Trias was deposited. Mention may be made of the work of Goodchild, 1896; Mellard Reade; Bonney, 1900, 1902; Lomas, 1907; and Bosworth, 1912. Their papers show a general concensus of opinion that the deposit took place under continental and desert conditions in an extremely arid climate. An important discovery made in 1899 by Mr. R. F. Martin near Mountsorrel, further finds at that place and near to it, and revelations made later at Mountsorrel itself, all seemed to the writer to give decisive confirmation to this conclusion. But doubt has been thrown upon the validity of some of this evidence, and it will be well to re-examine it.

Much has recently been written about the compressional theory for the origin of Rift Valleys in Africa, and the supposed reversed faulting of their sides, and so little has been published about the evidence for their normal faulting, that those who have not had the opportunity of working in rift valley areas may possibly obtain a rather one-sided view of the problem. It seems fair, therefore, to ask for space in the Geological Magazine to reflect on the case against the compressional theory, and to bring forward in general some of the evidence in support of normal faulting.