The above five insect remains, claiming affinity with the modern genus Gryllacris, of the order Orthoptera, retain for the investigator no characters in common, but such as may be afforded by the central portion of the principal disk or internomediate field of the elytron, and by the lesser marginal field. From comparison of these areas in the specimens from the Coal-measures, as regards configuration and venation, a certain similarity of design is observed, and a general correspondence detected. By taking Heer's descriptions and figures as data, this character is seen to be reproduced—less markedly distinct from the type observable in certain species of the modern genus of Burmeister—both in the profile of G. Ungeri and in other fragments preserved to us in the Eocene strata of the Continent. Complete identification of these species must be the reward of future investigators.

In his letter to the Editor, inserted in the last Number of this Magazine (p.332), Mr. Mallet says he is “compelled to repeat” the statements he had persistently made, and I had more than once denied, as to my having, “in almost all my writings,” upheld “the moribund thin crust and liquid nucleus theroy”and “ Hopkins's fiery lakes.” He defends himself from the charge of having “misapprehended,” as was suggested in an Editorial foot-note to his paper, or, as I more truly phrased it, “misrepresented,” my views on these subjects, refusing to be bound by what I may have “written in the scattered magazine articles ” to which he was referred, on the plea that “an author's notions are usually gathered from his acknowleged systematic works.”

The greatest extent of the displacement of the earth's centre of gravity, and consequently the greatest rise of the ocean resulting from that displacement, would of course occur at the time of maximum glaciation, when the ice would be all on one hemisphere. But owing to the following circumstance, a still greater rise than that resulting from the displacement of the earth's centre of gravity alone might take place at some considerable time, either before or after the period of maximum glaciation.

This neighbourhood has already been described by several authors, —the most complete account of the Tertiary beds being by Dr. Fraas, Aus dem Orient, 1867. Dr. Figari Bey, in vol. i. of Studi Scientifici sull' Egitto; H, Bauerman, Esq., and Dr. C. Le Neve Foster, in the Quart Journ. Geol. Soc. 1869, vol. xxv. p. 40, have also written on the district, the latter observers referring especially to the occurrence of Celestine in the Moccattam quarries.

In mapping the boundaries of the Lias in that part of Yorkshire where the Cretaceous rocks overlap the Jurassic, the Red Chalk becomes extremely useful as a guide, especially as the springs constantly break out beneath it, and give good opportunities for its examination and that of the subjacent strata. Some points of interest have thus obtruded themselves upon one's notice. Its range in Yorkshire may be described as first northwards and then eastwards. Though much covered, by Boulder-clay in the latter portion, it may be traced almost step by step along the former, except where it appears to be absent.