All those British geologists who have interested themselves in the long-vexed question of the geological position and true mode of origin of the Metamorphic rocks of the Highlands of Scotland must have read with the greatest interest and pleasure the clear and vivid “Report on the Geology of the North-West of Sutherland,” by Messrs. Peach and Horne, in the pages of “Nature” for November last; and the manly and candid Introductory Observations by the Director-General of the Geological Survey. Not only does the publication of this Report put an end to one of the most keenly agitated controversies in the history of British Geology, but it explains and harmonizes the diverse views of the contending parties. The issue appears to me to be most creditable to all concerned. For many years the Highland controversy has appeared to outsiders, and to those geologists who were unaware of the difficulties attending the stratigraphy of the older rocks, as a trivial dispute between the Geological Survey on the one hand and a few misguided amateurs on the other.

In previous communications to the Geological Magazine I have described at some length the petrographical characters of the lavas and tuffs of the Cheviot District. It was proved that they are, at any rate for the most part, of an andesitic character, and that some of them are so little altered as to be thoroughly entitled to the term andesite, unless we are prepared to adopt the unphilosophical system of making geological age, per se, a factor in petrographical nomenclature. If we leave out of account the modifications in structure and composition which have been superinduced on the rocks by the various agents of change, then the Cheviot lavas and tuffs belong to the three fairly well characterized groups of the augite-, hypersthene-, and mica-andesites.

Bibliography, etc.—This somewhat insignificant fossil approaches several of the small granulated or tuberculated species of Trochus (or Monodonta), which are distinguished by a completely conical outline, resulting from a close suture and perfect flatness of the whorls. Although without description, Phillips's figure is characteristic, and it is somewhat singular that this species was not recognized by D'Orbigny amongst the fossils of the French Jurassic. The typical form is confined, in Yorkshire, so far as I know, to the Scarborough Limestone (zone 3), where it is rare, and, for the most part, so imperfectly preserved, that accurate description is a matter of some difficulty.

Up to December last the most ancient fossil insects known were the six fragments of Neuroptera, obtained by Mr. C. F. Hartt, from the Devonian rocks of New Brunswick, which were described by Mr. Scudder in Vol. V. of this Magazine. Although these six fossils were the oldest known insects, it seemed unlikely that they, or even the families or genera to which they belonged, were the most ancient representatives of their class. The first appearance of insects on the Earth was probably contemporaneous with that of land plants, and as remains of this division of the Vegetable Kingdom had been discovered in Silurian rocks, it seemed not unreasonable to assume that insects might have existed at an earlier period than the Devonian. The recent discovery of the wing of a cockroach in rocks of Silurian age at Jurques, Calvados, France, no longer leaves the question of the occurrence of insects at an earlier period than the Devonian a matter of speculation.

Since describing the skull of Anthracotherium Gresslyi (= Hyopotamus Gresslyi. Rüt.) in the last Number of the Magazine (p. 63), I have observed that the right maxilla of a small anthracotheroid from the Upper Eocene “Bohnerz” of Canton Vaud, Switzerland, has been figured by Pictet in his “Matériaux pour la Paléontologie Suisse—Vertèbres de la Faune Eocéne, Supplement, pl. xxiv. fig. 5,” under the name of H. Gresslyi. The British Museum has recently acquired some upper true molars from the same formation agreeing precisely with those of Pictet's specimen; and a comparison of these teeth with those of the Brit. Museum specimen of A. Gresslyi (figured in my memoir already quoted) shows that they are quite different;— being distinguished by their slightly inferior size, the more inward inclination of the outer surfaces of the external columns, as well as the more distinct loop connecting these columns. These teeth agree, in fact, with those of brachydont species of Hyopotamus, like H. porcinus. Pictet's figure also shows that his specimen differs from Anthracotherium Gresslyi in having an elongated, instead of a triangular Pm. 3.

AS one of your reviewers now some years ago criticized unfavourably the method of representing geological structure in maps by contour lines upon a bed of coal or other rock, and as, like him, most geologists are not yet practically familiar with the method, useful though it be, and nobody that might be thought wholly unbiassed has replied in your pages to his attacks, it may not be improper to call your attention to the unprejudiced opinion and explanation of Mr. Charles A. Ashburner, the geologist in charge of the survey of the anthracite region, under the Geological Survey of Pennsylvania, who has up to this time published 26 large sheets of most elaborate maps and sections with one volume of text. After careful examination before adopting the method and after using it several years he writes of it in the report (page 8) as follows:—