After he had published his account of the geology of the Solomon Islands, Dr. Guppy was good enough to present to the Museum of Practical Geology a series of typical specimens showing the chief varieties of calcareous and argillaceous deposits met with in the islands. This collection includes rocks, washings, picked organisms, with a few microscopic slides, and it constitutes a series very valuable for reference.

In 1891 Professor A. H. Green wrote an interesting notice of two books, both of extreme value to the petrological student, viz. Cole's Aids in Practical Geology and Hatch's Introduction to the Study of Petrology. In the course of his review the Professor remarks: “In dealing with the foliated rocks, the author touches on the debated point of the ‘true schists.’ We are pretty well used to this phrase, and have waited long in the hopes of being told what constitutes a ‘true schist,’ but our patience has not yet met with the reward it merits. The author is of opinion that ‘the alleged distinction between schist-like rocks and schists of pre-Cambrian age requires great delicacy of definition.’ This is delicately put, and will command the assent of most geologists” (Nature, vol. xliv, p. 26).

During the last few months two spines, or Ichthyodorulites, belonging to the genus Listracanthus, have come under my observation. Since both are well-preserved specimens, and not hitherto recorded from the English Coal-measures, some information as to their appearance and stratigraphical position may be of interest.

The differences in chemical composition between spherulites and the matrices which contain them have been determined by many analysts. Michel Lévy, in a long and comprehensive paper, quotes some former analyses by Delesse, comparing them with his own, which they closely resembled. Lagario gives many analyses which are especially valuable, as he compares results from acid with those from intermediate and basic rocks, and finds a distinct difference between them. The relations of these results will be briefly considered at the end of the present paper.

During the years 1890–2 an important boring was made in the Red Marl, rather under a mile NNE. of Altcar and nearly two miles east from Formby station. Previous to 1890, the formation was supposed not to exceed 400 feet in thickness, the amount proved at Birkdale many years ago.

In his article in the last number of the Geological Magazine Mr. A. R. Hunt points out a number of differences in the use of the terms “schist, slate, phyllite, and foliation.” The usage of English-speaking peoples has long ago restricted the word “schist,” so that it is no more an equivalent of the French “schiste” and of the German “schiefer” than “mutton” is of “mouton.” Prof. Bonney's position is, however, one of exceptional restriction, as he himself has always carefully pointed out. The terms “phyllade” and “phyllite” are surrounded by less controversy. I regard both as unnecessary, seeing that we cannot have names for every gradation from a clay-slate to a mica-schist; but it is fairly clear that the original “phyllades” were slates containing some mica. The term was used in 1813 by Brongniart (“Essai d'une classification des Roches mélangées,” p. 35), who ascribes it to the joint authorship of himself, Brochant, and D'Aubuisson. He gives as a synonym, “Thonschiefer mélangé des minéralogistes allemands,” and defines the rock as having a ground of clay, with mica, quartz, felspar, amphibole, chiastolite, etc., in it, either together or separately; “structure feuilletée.” None of the types which he describes are free from mica. D'Aubuisson de Voisins (“Traité de Géognosie,” tome ii, p. 93) in 1819 devoted one of his elaborate disquisitions to Phyllade, giving as synonyms “Thonschiefer; Clay-slate; Ardoise, schiste de Saussure et des anciens minéralogistes; Schiste argileux de M. Brochant.” D'Aubuisson objects to the restriction of “schiste” to any one species of rock, and keeps phyllade distinct from those clays which are derived as detritus from pre-existing rocks. He says that the surface of phyllade is sometimes smooth, sometimes deeply striated, as if puckered up (“froncée”); and he shows how the true type of the rock is approached by gradations from mica-schist, until the mica and quartz are so finely divided as be indistinguishable, save for some flakes of mica and granules of quartz embedded in the apparently homogeneous ground. The justification for using “phyllade” as a term intermediate between mica-schist and common slate is to be found in the passage (p. 97) “Le phyllade passant du schistemicacé à l'ardoise, par des nuances insensibles et diversifiées sous tous les rapports, le nombre de ses variétés est presque indéfini.” D'Aubuisson believed the fissile structure to be parallel to the stratification, and combated the acute views of Voigt, who had observed a strong divergence between the two structures in Thuringia.

The interesting section at Clava, near Inverness, was first examined geologically by Mr. James Fraser, C.E.; and his remarks on it were published in the Transactions of the Geological Society of Edinburgh, vol. iv, part 2, and in the Transactions of the Inverness Field Club, vol. ii.