The hornblendic and associated rocks referred to in the above title cover a large part of the township of Cortland—the north-western of Westchester County, New York—between Croton River on the south and the parallel of Peekskill on the north, an area of about 25 square miles. They differ widely from the ordinary rocks of the county, and may well be designated the Cortland series. In fact, a series so remarkable in constitution, so diversified in kinds, and so full of geological interest, is seldom found together within so small an area anywhere on the globe. They reach the banks of the Hudson just south of the Peekskill railroad station, and at several points beyond; yet considerable portions of the shore region are occupied by narrow strips of common kinds of mica schist and gneiss, and occasionally limestone.

About twenty years ago, two fossil animals of great interest were found in the lithographic slates of Bavaria. One was the skeleton of Archæopteryx, now in the British Museum, and the other was the Compsognathus preserved in the Royal Museum at Munich. A single feather, to which the name Archæopteryx was first applied by Von Meyer, had previously been discovered at the same locality. More recently, another skeleton has been brought to light in the same beds, and is now in the Museum of Berlin. These three specimens of Archæopteryx are the only remains of this genus known, while of Compsognathus the original skeleton is, up to the present time, the only representative.

Shropshire was always considered by Sir Roderick Murchison as one of the districts in which his Upper Silurian rocks could be most advantageously studied.1 We propose, therefore, in this communication to offer some few notes on the Geology and Palæntology of the Wenlock and Ludlow series; illustrated by the Brachiopoda, reserving for the present what we may have to communicate with respect to the Upper Llandovery.

The wooden defences which protected the cliff opposite the Alexandra Hotel at Bridlington Quay having been removed last autumn, preparatory to the erection of a more substantial concrete wall, a section was, for a short time, exposed which had long been hidden (see section P1. VIII. p. 537). The length of this section was a little over 1,000 feet, extending from Sands Cut to Carr Lane; its average height was about 30 feet.

The extent of these bands, their number, uniformity of direction and apparently of dip, and the identity of the material constituting them with beds of the schist, especially the more northern, are such as to warrant the following section (Fig. 15).

This fine specimen, which has been so faithfully rendered in two views by Miss G. M. Woodward, was thund by me, together with portions of other individuals of the genus, in some red finely-sandy or silty beds, interstratified with grits, in the Cutting of the new road on the eastern side of Lincombe Hill at Torquay. The beds are traversed by a coarse cleavage dipping south, which usually ignores the hard grit bands. We may call them for the present the “Lincombe, Warberry, and Smuggler's Cove grits,” and their probable equivalents will be considered shortly.

The following facts were observed during a visit to Anglesea and Carnarvonshire in company with Prof. Hughes in the early part of July. They still further bear out and confirm the evidence given in a short communication to the Geological Magazine for May, 1881, bearing upon the position of the Twt Hill conglomerate. Among the arguments brought forward against the Cambrian age of that conglomerate, much stress has been laid upon the absence fromit of felsite pebbles, which are so characteristic of the Cambrian conglomerate in the neighbourhood of Bangor.

In the tenth volume of this Magazine, a correspondence appeared upon the subject of “True and Apparent Dip,” which was started by Mr. Penning, and continued by several able geologists. The object of the present article is to call attention to another branch of the same subject. We are all acquainted with “Sopwith's Models,” in which are experimentally shown the outcrops, or “traces,” of plane strata upon variously curved surfaces. We now are about to refer to the outcrop of curved strata upon a plane surface. I was led to examine this question from the following circumstances.

As bearing upon the subject of Mr. J. Arthur Phillips's interesting and valuable paper in the last number of the Quarterly Journal of the Geological Society, entitled, “On the Constitution and History of Grits and Sandstones,” a description of a cliff section of blown sand now to be seen on the coast at Crosby may not be without value. The section in question, which attracted the attention of a local geologist, Mr. William Semmons, and myself, is at a point on the coast where the sea is encroaching upon the sand-dunes, and washing them away at the base leaves the face almost vertical. The resemblance of the sand to rock is most striking, presenting all those peculiarities of cross-bedding and lines of erosion we are familiar with in some of the Triassic sandstones of the neighbourhood. During the last twelve years, in walks along the shore, I have often observed the laminations of the blown sand disclosed by denudation, but never so strikingly as in the present case. The beds not only display delicate laminations, but stand out in ribs and cornices, simulating Gothic mouldings in pi'ofile. On trying how so loose a material as blown sand could retain these projecting forms, I was surprised to find the projections comparatively hard and solid. On breaking a piece off, the reason became apparent; for instead of the usually dry incoherent grains of sand, below the surface-skin the sand was quite damp. A very little addition of siliceous or calcareous cement would turn the mass into rock.

The old lacustrine deposits of Ireland do not seem to have attracted so much attention from geologists as they deserve. By the old lacustrine deposits, we understand the dried-up lakes at present occupied by peat-bogs, with their underlying beds of marl and clays. During the past century it was known that in these bogs, or in the marl-beds beneath them, were found antlers and bones of a gigantic extinct deer, which Professor Owen named Megaceros Hibernicus, and now popularly known as the “Irish Elk,”1 not that it was exclusively confined to Ireland, its remains having been found in England and Scotland, also in France and Germany, and it is even reported to occur in caves as far east as the Altai Mountains in Asia.

The above brief description of the Cortland rocks prepares the way for a consideration of their relation to the other rocks of the county. The following questions arise: Are they one with the latter in system ? are they rocks of an earlier system ? or are they eruptive rocks, and not metamorphic, and hence, of no bearing on the general question as to the age of the Westchester limestones and the associated schists ?

In France deposits of the same kind, such as those at Menchecourt, are familiar enough. To complete our merely illustrative list of examples, I would quote the vast deposits found in the offing of the Thames, and right away to the Dutch coast. Dr. Bree says that the bones occur in such quantities on the sea-bottom off Dunkirk that the sailors call it the Burying Ground (Leith Adams's Mem. on Elephas primigenius, p. 73).

[M. C. Struckmann, who has already published an elaborate treatise on the Upper Jura of the neighbourhood of Hanover, has communicated to the “Neues Jahrbnch für Mineralogie, etc.” (1881, Bd. II. pp. 77–102), a comparison, founded mainly upon palæontological evidence, between the Upper Jurassic deposits of that district and England, and a statement of the conclusions at which he arrives will be interesting to many English geologists.

In his valedictory address as President of the Edinburgh Geological Society, at the close of the session 1879–80, Mr. Milne Home reviewed our recent paper on “The Glaciation of the Shetland Isles.” In his address he not only called in question our conclusions regarding the direction of the glaciation of these islands, but likewise referred to the discordance between the observations of Mr. C. W. Peach and ourselves. As much of this adverse criticism is based on a misconception of the real nature of the evidence bearing on the question, we are anxious to reply to some of the points in the address which might mislead those who are unacquainted with the subject.

In a previous paper we showed that the extinction of the Mammoth was sudden, and was accompanied by a sudden change of climate throughout Northern Siberia, which enabled its soft parts to be preserved intact. We did not mean that the change of climate was the cause of the Mammoth's extinction. This it clearly was not, for this change on a large and marked scale was apparently confined to Siberia, while the Mammoth disappeared from a much wider area, where this climatic revolution could not have been so fatal. A sudden change of climate could not account for a catena of Mammoth carcases found buried several feet underground from the Obi to Behrings Straits. If they had been killed by the cold merely, their bodies would have lain on the surface where they fell and become long ago the prey of the predatory animals. Nor again can we, with such a postulate merely, account for the remains occurring in many cases in hecatombs, and in many cases also with a mixture of various species of animals. The cold would hardly have destroyed the bears and hyænas which are found linked in a common fate with the Mammoths and Rhinoceroses. Nor, as we shall see, would a mere change of climate, however severe, account for other factors in the problem. The change of climate accounts perfectly for the preservation of the carcases, which preservation again necessitates the conclusion that that change was a sudden or very rapid one; but we have clearly still to seek the real cause of the disappearance of the animals of which the change of climate was a concurrent effect.

By the kind communication of my friend, the Rev. P. B. Brodie, M.A., F.G.S., I have been able to study two very striking wing-fragments from the Coal-measures of Great Britain, which are interesting, not only from the excessive rarity of such remains in this country, but also from their relationship to the two or three already known.

Having considered the conditions under which the Mammoth lived in Siberia, we now propose to turn to the parallel problem in Europe, and to show that the mode of life was practically the same in both areas, and that the problem which has to be solved is virtually the same in both.

The International Geological Congress had its origin at Philadelphia in 1876, when, largely by the influence of Prof. Jas. Hall and Dr. Sterry Hunt, arrangements were made for a meeting of the Congress at Paris. This was held during the months of August and September, 1878, as one of a great series of International Congresses, embracing all branches of Science and the technical applications of the same. The full reports of these meetings are contained in 32 8vo. volumes; that on Geology forming No. 21 of the Series. In the Geological Congress papers were read and discussed on numerous subjects connected with the science.

The fossil, which forms the subject of our Plate, is a most welcome addition to our list of Middle Devonian fossils, and I am much indebted to my friend Mr. Arthur Champernowne, F.G.S., for the opportunity of describing it.

As in the previous notes (Geol. Mag. Decade II. Vol. VII. No. 10, p. 447, 1880), so in the present, it is deemed desirable to give in the first instance a complete list of all the examples of the groups under consideration, which have hitherto been recorded, and then, having examined each critically, finally to give a corrected list.