The genus Dendrerpeton was established by Owen on the evidence of remains found by Sir C. Lyell and the writer in an erect tree at the South Joggins in Nova Scotia in 1852. Other specimens were afterwards obtained, and the most complete, presented by me to the Cabinet of the Geological Society, was found in 1861, and described in my “Airbreathers of the Coal Period.” These remains rendered it certain that the animal belongs to the order Labyrinthodontia, and it is regarded by Lydekker as the type of a family in that group.

These opinions of Mr. Campbell, however clearly and precisely stated, are so strong and emphatic, that I wish to confirm them by those of another experienced geologist, who worked much among the Himalayas, namely, General McMahon. In “Notes of a Tour through Hangrang and Spiti,” published in the twelfth volume of the Eecords of the Geological Survey of India, he describes the existing glaciers and their remains in the district, and then says: “I do not know whether any one has ever supposed that the Himalayas were covered during the last Glacial period with an ice-cap, but I may note that whilst I saw nothing to favour such, an idea, I saw much to negative it. The contour of the hills and valleys in those parts of the interior of the Himalayas that I have visited is sharp and angular, and where rounded outlines are seen, they are sufficiently explained by the action of subaeiial forces on comparatively soft and friable rocks.

These notes are in continuation of my former paper “On the Probable Origin of some Slates” (Geological Magazine for June and July, 1890). Since its publication I have endeavoured to obtain a little further knowledge of the constitution of the fireclays of the Coal-measures, which I regard as so well calculated to throw light on the origin of many slates, and especially I desired to get, if possible, a little more evidence as to the supposed regeneration of mica in them, in connexion with the intimately associated question of the rutile-needles.

Crystalline rocks containing neither felspar nor olivine have received but little or no attention, except from one or two American geologists. Dr. G. H. Williams has recently drawn attention to these rocks, of which he proposes to constitute a family of Pyroxenites coördinate with Rosenbusch's family of Peridotites; and has described from Maryland and North Carolina a type consisting entirely of monoclinic and rhombic pyroxenes, to which he gives the name Websterite. The occurrence of a similar rock in Northern Italy seems worth recording. Our specimens were collected by Mr. E. J. Garwood.

The consideration of the Archæan rocks of Finland, as pointed out in a previous article, naturally divides itself into two parts: I. The treatment of the stratified or foliated members of the series; II. That of the igneous or eruptive rocks. In describing the former, want of space compelled me to handle the subject in what I fear must be regarded as a very fragmentary manner. In addition I confined myself entirely to giving an account of the older members of the formation, omitting all mention of the younger schists, mica-clay slates, phyllites, etc., which go to make up what is in Finland regarded as corresponding to the Huronian subdivision. I did this from two reasons,—firstly, because I was personally better acquainted with the rocks in question ; secondly, because it seemed to me that it is the problem of the origin, sequence and composition of the older members of the series which at the present day possesses most interest for the student of the geology of the Archaean, and in consequence is the one with regard to which the greatest divergence of opinion prevails. In the present article I propose to give a short account of the more important eruptive rocks of Finland; but before proceeding to do so, it would not, I think, be out of place to furnish a short résumé of the conclusions to which the study of the foliated Archæan rocks of the country has led me, and which I believe to be thoroughly supported by the data published in my former article.