In the Geological Magazine for February the limestone-boulders in the Bowland Shales of School Share near Settle were redescribed by Dr. R. G. S. Hudson and the writer, and the conclusion reached that they represented a landslip from a fault-scarp raised along part of the Craven Fault-system during the mid-Carboniferous earth-movement. Whilst that article was in the press the writer became aware that great limestone-boulders occur in the Caney Shale of Oklahoma and that they have occasioned much discussion or even, owing to their size and varied fossils, uncertainty as to the age of the associated beds. His interest was piqued, for he recalled that a close comparison had been drawn by Bisat between the contrast of Bowland Shale (Culm) and Yoredale facies of sedimentation, displayed in the Craven Lowlands and in the Craven Uplands and the Yorkshire Dales, and a contrast in Oklahoma between the sedimentation in the Ouachita Mountains and that in the nearby Arbuckle Mountains.

It has long been known that garnet and other heavy minerals occur in many of the sedimentary beds of the North of England. Among such, where visual proof is easy, are the Inghoe Grits, particularly at Shaftoe, and the Dunstanburgh sandstone at Cullernose Point. Hutchings examined washings of the shales at Seaton Sluice and found zircons in large numbers, along with angular colourless garnet, rutile, anatase, tourmaline, sphene and barytes. In a later study by the same author of the sedimentary beds metamorphosed by the Whin Sill, it was shown that small garnets are very plentiful, especially in the calcareous shales, and are accompanied by augite, hornblende, epidote, sphene, idocrase, wollastonite and other minerals. Kellett made an extended investigation of the heavy minerals in the Coal Measures of County Durham and found 0·4 per cent of these in the sandstone under the Hutton seam (this is the only datum of Kellett's strictly comparable with our results). Zircon proved to be the commonest mineral in these beds; next in order came rutile and tourmaline, while garnet was quite subsidiary.

A Specimen in the Ludlow Museum, which appears to he the lost type of Sowerby's species Orthoceras attenuatum figured in Murchison's Silurian System, plate 13, fig. 25, p. 632, from the Wenlock Shale of the “banks of the Onny River, near Stretford Bridge”, has been recognized by Mr. T. D. La Touche in rearranging and cataloguing the collection of local fossils. Owing to the fact that the large piece of rock (D. b. 49 in La Touche's catalogue) on which it occurs was fastened down to a tablet so as to expose only another specimen of a smooth and different species of Orthoceras, it had been completely hidden from view, as it was on the lower side. The specimen not only agrees in size, general characters, and rate of tapering with Sowerby's figure (though the annulations are sharper and narrower than there indicated), but it was also collected by Dr. Lloyd, as was the type, as stated by Murchison. The horizon (Wenlock Shale) is recorded on the existing label, but not the locality. However, Mr. La Touche, from his intimate knowledge of the rocks of the district, considers that the locality may well be that given by Murchison. A small portion of the upper end of the shell is now missing, corresponding to the imperfect non-annulated piece shown in the figure, but it seems to have projected freely out of the matrix, so it may easily have been broken off. Otherwise the specimen is in the same good condition as when Sowerby drew his figure, and we can have scarcely any hesitation in identifying it on the strength of the above evidence.

The collection of rocks from the Sahara to be discussed was made by Captain D. R. G. Cameron, of the Royal Scots, during a journey across the Sahara from Kano to Algeria. The journey is described by Captain Cameron in his book A Saharan Venture (1928) and in a paper published in the Geographical Journal (lxxi, 1928, 538–59). The specimens were not collected in situ, which reduces their value somewhat. When one considers, however, that the collecting area is desert country where outcrops are comparatively scarce it is apparent that conclusions based on pebbles are not without value.

The salt of Jebel Usdum is not a product of the Pleistocene Dead Sea, nor of the lake which preceded it (in ? Pliocene time), the waters of which were fresh for a long period and deposited sediments, with a maximum thickness of 1,000 feet or more, which are younger than the salt.