A Small group of English Membranipora is strongly characterized by the possession of interstitial avicularia having one end raised into a smooth hood. No described species seems to possess such avicularia, except perhaps the form figured by d'Orbigny as Membranipora concatenata.

The thrips described herein was submitted to me by Professor Branca of the Geologisch-Palaeontologisches Museum, Berlin, and is one of a small collection of three examples in Baltic Amber. The genus is curious on account of the abnormal tube-like development of the tenth abdominal segment, which, however, is open ventrally for its entire length. In the form of the antennæ, so far as can be ascertained from the single example and the structure of the wings, Stenurothrips would seem to show affinity with the Neotropical genus Heterothrips, and for the present I regard the genus as falling in the Heterothripidæ.

In a recent number of this journal I advocated the systematic employment of a certain criterion in connexion with the classification and nomenclature of igneous rocks, that criterion being the ‘saturated’ or ‘unsaturated’ character of the minerals constituting a given rock. The terms saturated, unsaturated, and their derivatives oversaturated, undersaturated, and partsaturated, were not used in a strict chemical sense, but in a special mineralogical sense which was fully explained.

Of the Cirripedes obtained by the late Mr. F. Mockler from the Chalk Marl of Cambridge, two species, Zeugmatolepas mockleri. Withers, and Calantica (Titanolepas) tuberculata, Darwin, sp., have already been described and restorations given. The remaining material consists entirely of disconnected valves, and among these are (1) a number of valves referable to Pollicipes glaber, F. A. Roemer; (2) a few valves of P. rigidus, J. de C. Sowerby, together with some valves of a new species which is probably related to P. rigidus; (3) an important series of valves belonging to several species of Scalpellum allied to S. arcuatum, Darwin, and S. fossula, Darwin; and (4) some valves that do not belong to any of the species already mentioned, and which it will be convenient to describe here.

The shell-bearing gravels of the county of Wexford have become so well known on account of their fossil contents that the boulder-clays associated with them have received scanty recognition. Very diverse statements have been made in regard to thè position of the gravels in the succession of superficial deposits, and they have, frequently been confused with the 'marl' which was extolled by early writers upon agriculture. Nearly all the references to the manurial value of such materials in Co. Wexford refer to this marl, that is, to a shelly and calcareous boulder-clay. The gravels, however, have been commonly styled 'manure gravels' by geologists, and R. J. Griffith, as far back as 1836, distinctly states that the shells are sometimes so very numerous “that the gravel is raised for manure”.

I Claim to have now shown that the zone of O. pilula as established in 1912 for Hants and the Salisbury area holds good in its broad features also for Sussex, the Isle of Wight, and Dorset, and that it is almost equally constant in some of its minor features, especially the way in which it ends in a bed 2 ft. 6 in. to 3 feet thick with a flint seam in the middle of it and enclosed by two marl seams. I am only prevented by a single section in Hants from setting this up as the universal rule in all sections I have seen. In The Stratigraphy I assigned pits Nos. 1065, 1066, and 1067, the last of which will be more readily recognized as Mottisfont Whiting Pit, to the zone of A. quadratus, because on examining them for the purposes of that work for the first time since 1892 I had failed to find evidence of more than a seam of O. pilula without any others of the associated fossils of the zone. At the time of that examination all the pits were in a most unfavourable condition. Since then I have been keeping regular watch on the Whiting Pit (No. 1067), and I soon found that the subzone of abundantO. pilula must be represented at its base, and then that the upper belt of O. pilula in that subzone must be exposed: but it was only this spring that I was able to fix the absolute position of the boundary between the zones of O. pilula and A. quadratus in the Whiting Pit, and at the same time, owing to developments in the other two pits, to identify the cinctus belt in the old face and the lower belt of O. pilula in the new workings (and probably also at the lowest point of the old face) of Pit No. 1066, and the lower belt of O. pilula at the base of Pit No. 1065.

Sir,—I was much interested to read in your last issue the excellent review of Professor's Daly's latest work appearing above the initials “R. H. R.” May I draw your reviewer's attention to the fact that such points as the quantitative composition of the igneous rocks and the effects of assimilation upon them have been dealt with at some length in England before now, as your own pages can testify. In this Magazine as long ago as June, 1904, I entered a protest against the calculations made on a purely arm-chair basis by F. W. Clarke and A. Harker with regard to the former problem, and Mr. Clarke has, to some extent, modified his calculations as a result of this and a succeeding paper on the same subject. With regard to assimilation, a process intimately connected with the question of composition, Professor Grenville Cole has beencrying in the wilderness for many years past, and the late Dr. Johnston-Lavis has done good work in the same direction, while I attacked the problem on a much wider basis in a lengthy paper read before the British Association in 1905. This has been followed up by a general work on petrology, of which an expanded form was published by Messrs. Chapman & Hall last year. In substance itis a systematic exposition of the subject based on assimilation as opposed to the purely hypothetical ‘differentiation’ basis which has become so popular of late years. It may, perhaps, be added that Professor Daly has placed a great stumbling-block before many geologists by his advocacy of a prevailing basic magma, below the granitic one, as a primary feature of his work.

Sir,—On May 13 of this year a paper was read in the Geological Society of London by F. W. Penny, B.Sc, F.G.S., “On the Relationship of the Vredefort Granite to the Witwatersrand System” (see Geol. Mag., July, 1914, pp. 332–3), wherein the writer suggests “that the Vredefort Granite, instead of being ‘Archæan’, is of a post-Pretoria – pre-Karroo age, if not contemporaneous with, at least connected with, the same epoch of igneous activity as the ‘Red Granite’ of the Northern Transvaal”.