The fact of the occurrence of Rhizodus at Wardie has been known for a good many years. It appears as an addendum to a list of fossils from that locality published in 1861 by the Geological Survey of Scotland. The specimens hitherto collected, however, have been the merest fragments, consisting principally of detached scales. Almost the first fossil obtained by the writer from Wardie was a badly-preserved fragment of the jaw of Rhizodus containing teeth. Since then a few fragments have occurred referable to the same genus. From the fact that these were invariably found along a particular part of the beach, the suspicion was gradually awakened that they had been derived from a common source. This suspicion was confirmed by the discovery of the remarkable specimen which is the subject of this notice. It was found lying in the direction of the strike of the beds, its head seawards, its tail to the shore.

Irish land, which has so long puzzled our statesmen, proves to be equally perplexing to our geologists. The metamorphic rocks have excited much controversy, and new problems are emerging. Prof. Hull claims to have found Laurentians in Donegal, Gaiway, and intermediate localities, while Mr. Kinahan, in this Magazine, sums up the evidence for the old opinions. As I have recently studied one of the areas referred to by the latter, I submit a few comments on a part of his paper. I am much indebted to him for the very kind and courteous manner in which he abridged my work by indicating the most important sections, and regret that I must ungratefully repay the obligation by differing widely from his conclusions.

Looking carefully through Herra Thoroddsen's researchful and excellent paper, with the above heading, published in the October (1880) Number of the Geological Magazine, I notice that two or three errors have crept in.

The mineral composition of rocks, often an important test in comparatively unfossiliferous formations, such as the Trias, becomes of supreme value amongst the Archæan groups. It is very frequently the only kind of evidence available, and, used with due caution, may lead to decisive results. In Anglesey, as illustrated in Fig. 1, and already described, it is nearly as conclusive as the testimony of organic remains; for the great similarity of the dark schist in two areas so near together renders their correlation in the very highest degree probable. The gneissic rocks of the Malvern Hills have been classed as Laurentian on the ground of the lithological resemblance between the two groups, though 3000 miles apart; and the determination has been generally accepted. But in such a case as this, high probability is all we can expect. Other gneissic and schistose systems have been described in America, though none of them so closely resemble the Malvern series as the Laurentian.

The following list includes all the species belonging to these two groups which have hitherto been recorded from the “Forest Bed Series.”

I have read with interest, the reply by Messrs. Peach and Horne in the August Number of the Geological Magazine, to my criticisms on their theory, that the glaciation of the Shetlands is due to a mer de glace from Scandinavia.

In comparing the relative thicknesses of the Welsh-English and the Scotch Carboniferous series for lecture notes, I have found it difficult to obtain from books definite statements on this point as regards some groups of these strata in Scotland. After considerable reading I gather the following information.

In the Report on the Geology of the Henry Mountains, Rocky Mountain Region, Mr. G. K. Gilbert, of the U.S. Geographical and Geological Survey, points out that many of the intrusions of eruptive rocks now exposed had a deep-seated origin; the molten rock having filled vacancies in the rocks, and never coming to the surface until they were exposed by denudation or by faults. To quote our author, “The lava … instead of rising through all the beds of the earth's crust, stopped at a lower horizon, insinuated itself between two strata, and opened for itself a chamber by lifting all the superior beds. For these masses of eruptive rocks, Gilbert proposes the name laccolite (Gr. lakkos cistern, and lithos stone). In the Cos. Wexford and Wioklow some of the protrusions of eruptive rocks are entitled to this name, the rocks having congealed in cisterns below the surface of the earth; there are, however, some marked differences between them and the laccolites of the Henry Mountains. The latter were intruded into nearly horizontal strata, the laccolites only consist of one kind of rock, while the adjoining rocks seem to have been very little altered. But the Wexford and Wicklow laccolites, on the other hand, were intruded into highly disturbed strata, they are made up of a variety of rocks, and always the aquo-igneous action due to their intrusion—‘ baked ’ or altered, a greater or less thickness of rocks about them.

The genus Purpuroidea was described by me in 1848 from three species in the Great Oolite of Gloucestershire, and published in the Annals and Magazine of Natural History, accompanied by woodcuts representing one of the Species. Before that period M. Buvignier had described and figured three species of the same genus from the Coral Rag of France, Mem. Soc. Philomath. Verdun, 1843, accompanied by plates illustrating the Species, which he assigned to the genus Purpura; these figures were for the most part insufficient for the purposes of generic discrimination, and founded upon specimens more or less imperfect; one of them was believed by me to be identical with the species figured in my woodcut, and was accordingly named by me Purpuroidea nodulata, the name of the Species having been adopted from the Murex nodulatus of Young and Bird, which was also believed to be identical with the Gloucestershire species.

In drawing attention to some characters of the Berlin Archæopteryx, it should be stated that I only know that specimen from a photograph taken before the slab was fully developed; and therefore while I believe the following results to be trustworthy as indicating specific and it may be generic differences, it is possible they may hereafter be slightly modified.

Cambrian of Westrogothia, Oland, etc.—The Cambrian Rocks are shown in several other localities in Scania. The basal sandstones (Lugnas or Eophyton sandstones) near the Baltic coast, near Delperöd. The Hardeberga sandstones (Fucoid Sandstone) are found wherever the Archæan is bared, as near Rostånga, Lund, Eljaröd, and Cimbrishavn. Sections of the Alum schists are rarer. The most perfect is that of Kiviks Esperöd on the Baltic, where the Coronatus Limestone or Exsulans horizon of the Parad. Tessini zone well developed. The identity between its palæontological sequence and that of Andrarum was demonstrated by Nathorst in 1876.

During a recent visit to the tunnel now in course of construction beneath the Severn, I was taken by my friend Mr. Evan Jones, of University College, to examine a heap of Triassic pebbles and conglomerate, which had been exploited from the bottom of one of the shafts of the tunnel on the Portskewet side of the river. My attention was at once arrested by the striated and polished surfaces presented by many of the pebbles, and the results of the short examination I was able to make of them are embodied in the following note.

Cretaceous.—Lying everywhere quite unconformably below the Tertiary beds are the Cretaceous rocks, which constitute on the coast the true Coal-bearing horizon of British Columbia. These rocks probably at one time spread much more widely along the coast than they now do, but have since been folded and disturbed during the continuation of the process of mountain elevation, and have been much reduced by denudation. Their most important area, including the coal-rnining regions of Nanaimo and Comox, may be described as forming a narrow trough along the north-east border of Vancouver Island, 130 miles in length. The rocks are sandstones, conglomerates, and shales. They hold abundance of fossil plants and marine shells in some places, and in appearance and degree of induration much resemble the true Carboniferous rocks of some parts of Eastern America.