Nearly twenty years ago L. R. Cox published (Ann. Mag. Nat. Hist., 1925, p. 169) an account of “Bajocian-Bathonian outcrop in the Jordan Valley and its Molluscan Remains”, which was then, according to the author, “the first authentic record of Jurassic rocks in the Jordan Valley region, or anywhere between Northern Sinai and Mount Hermon, in Syria.” Miss Helen Muir-Wood in the same issue analysed the Brachiopod fauna of these rocks.

Increasing attention has been paid in recent years to the reconstruction and interpretation of stream profiles. It might therefore be well to examine a little more closely the way in which the curve of water erosion and the polycyclic valleys are produced. In this paper these problems are considered in the light of some preliminary experimental work recently described in this Magazine (1).

In a recent description of a composite teschenite-picrite sill at Saltcoats in Ayrshire (Patterson, 1945), mention was made of a potash-rich variety of lugarite which occurs as a differentiate of biotite-teschenite. The latter rock was emplaced at an intermediate stage in the intrusion cycle of the sill, being preceded by a flow-banded teschenite and followed by hornblende-picrite. Differentiation of the biotite-teschenite took place in situ and had proceeded to a considerable extent before the picrite was intruded along the middle portion of the former rock, splitting it into an upper and a lower layer. Richness in volatile constituents was a characteristic of the biotite-teschenite magma and facilitated the process of differentiation (Tomkeieff, 1937, p. 85; Smyth, 1913, p. 33). The separation of an alkali-rich fraction which resulted, is seen in the field by the appearance of pink analcitic patches or “blebs” in the teschenite at a distance of a foot or so from the margins. Further from the contacts, where cooling conditions were more gradual, these analcitic areas increase in size and frequently coalesce to form veins, which themselves intrude adjacent areas of biotite-teschenite. The veins are pink in colour, and contain varying amounts of conspicuous acicular crystals of barkevikite and titanaugite. Petrologically they are similar to the lugarites of the Scottish Permo-Carboniferous suite (Tyrrell, 1917). In chemical composition they also resemble the type lugarite, with the important exception that the Saltcoats rock is much richer in potash, although the sum of potash and soda is little different. A close analogy is provided by covite, from Magnet Cove in Arkansas (Washington, 1901). On account of the close relationship of the Saltcoats rock to the Scottish teschenites, it was preferred to name the rock potash-lugarite.

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.

In the course of an examination of Lower and Middle Pleistocene Beds at Kanam and Kanjera, on the southern shore of the Kavirondo Gulf of Victoria Nyanza, exposures of strongly disturbed lacustrine beds were located. The remarkable character of the deformation, at a locality where the possibility of a compressional origin could be excluded, led Professor P. G. H. Boswell (with whom the occurrence was discovered) to suggest that a short account should be published.

The area covered by Permian formations in the vicinity of Irwin River, Western Australia (see Text-fig. 1) has been visited many times by members of the Department of Geology, University of Western Australia, with parties of students for field instruction in mapping. In 1939 the author collected a suite of specimens from the principal beds of the Coal Measure Series for heavy mineral investigations, the results of which are recorded in this paper.

The River Erewash as it leaves the Erewash Valley Coalfield passes southwards through a gap in the Triassic scarp. On either side of the river, as it enters the gap, lie the twin settlements of Stapleford and Sandi-acre. The former spreads along the river flat at the foot of the scarp where this merges into the river bluff known as “Bob’s Rock”. At this point there is a quarry in the Bunter Sandstone situated behind St. John’s School. In the autumn of 1939 Mr. C. R. Vickers, the head master, drew my attention to the fact that the quarrymen were finding a number of bones in the sandstone. Though rather sceptical about the authenticity of such a find in the Bunter I visited the quarry. After inspecting the bones I was shown the precise spot where they occurred. This lay in the top part of the quarry face which was about 40 feet high. As looked at from the floor the sand at that spot was seen to fill a hole descending into the rock to a depth of about 7 feet and having a width, in its lower part, of about 2 feet.

Formerly there were several surface brine springs in the North-East Coalfield; to-day there are none. From the many accounts of their occurrence nothing has been learned of their exact position, and very little of the composition of their waters. The earliest record, made in 1684, described the Butterby spring (Todd, 1684), and then at various times during the next two centuries brine springs at Framwellgate, Lumley, Birtley, Walker, Wallsend, Hebburn, and Jarrow were noted. In particular the Birtley salt spring is often mentioned, and on the 6-in. Ordnance map, Durham No. 13, 1862 edition, it is sited to the south-east of the village. Although no record has been found there must have been either a brine spring or well at Gateshead, for the name of the present-day suburb, Saltwell, is very old, and brine springs are still active in the coal workings of that area.

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.

During a recent examination of some Coal Measure non-marine lamellibranchs in the collections of the British Museum (Natural History), my attention was drawn to a specimen from the Sowerby Collection labelled “Unio subconstrictus J. Sow., Coal Measures, Derbyshire”. On the back of the specimen were the remains of an original label, partly defaced, which some previous worker had endeavoured to read, for the words “Chapel … Sheffiel[d]” had been neatly copied on to another label affixed to the specimen.

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.