Early in the year the present writer published some notes on the Lower Devonian Fishes of Campbellton, New Brunswick, collected by Mr. Jex in the summer of 1891. Since that date the remainder of the collection, comprising a very large series of specimens from the Upper Devonian of Scaumenac Bay, in the Province of Quebec, has been acquired by the British Museum; and materials are thus forthcoming for some further observations.

Although the old-fashioned ideas as to the association of different minerals held by Breithaupt and others have been found to require much modification, there are still certain rules which hold with a high degree of generality. They are, indeed, merely consequences of the principle that the most important of the factors which determine the mineralogical constitution of an igneous rock, is the chemical composition of the magma from which it is formed. Roughly speaking, we may say that original free silica and acid silicates occur characteristically in acid rocks, more basic silicates in basic rocks.

It is a pretty well recognized fact that Obsidian is a hydrous silicate of indefinite composition and your fusion experiments confirm that fact. Now molten obsidian may give off its H2O in consequence of two processes—by simple vesiculation, or by the individualization from the glass of a definite anhydrous silicate. More commonly these two processes have gone on together, but modified by the vicissitudes of temperature that the molten aquiferous glass is exposed to during its eruption.

In the Geological Magazine of last year I described a system of Miniature Faulting observed by me in a fine bed of banded silty clay at Nevin, Carnarvonshire. This year I have had the good fortune to observe Faulting in Drift on a much larger scale in the neighbourhood of St. Bees, Cumberland, which is highly instructive and explanatory of several features of Normal Faulting which the other illustration did not touch.

The recent contribution of Mr. Reade to Glacial Geology (GEOL. MAG. July, 1892, p. 310, et seq.) is a challenge which I take up in default of a worthier champion.

As one who has for many years made a special study of the lunar surface, and who is thoroughly convinced that the geologist alone can now extricate selenology from the slough in which it has hopelessly stuck fast, I venture very briefly to lay the case before your readers, in the hope that some one will come forward and help us.

In a letter in the last Number of the GEOLOGICAL MAGAZINE, Mr. Jukes-Browne takes me to task, with some asperity of language, for my views on the true horizon of the Mammoth, You will, I am sure, allow me to reply to him. He speaks of my “looking down from some literary height upon practical geologists in the plain,” and goes on to say that I have “no practical experience as a geologist, and bids me study the facts in the field.”