It has not hitherto been clearly made out in what way these Carboniferous patches are related to each other. Some have considered it doubtful whether the three former are in any way represented in the Coalbrook-dale Field. The prevailing impression is, I believe, that the Clee Hill Fields are quite distinct in point of age from any of the Coal tracts surrounding them, and were formed in a depression sufficiently low to receive the Millstone Grit which we find to be wanting in the extensive Coal-fields to the East and North-east, except, let me observe, along the Western margin of the Coalbrook-dale district, where it is not well developed, but still represented. Eastward of that margin, however, it thins out rapidly, and gives way to the Silurian flooring of that Coal-field.

It has always been difficult to account for the feet that, while Moraine Drifts occur at such low levels in the Lake District, Marine Drifts are found at such high elevations in the surrounding district. Mr. Mackintosh's new facts throw some light on this phenomena, but do not entirely explain it, owing to his having given, in my opinion, far too little importance to the second Glaciation experienced by the Lake District after its emergence from the Glacial Sea.

The fine series of Fossil Fishes in the National collection is exhibited in and constitutes the principal feature of Boom II. in the Northern Geological Gallery. The arrangement adopted is in accordance with the classification of Prof. L. Agassiz, as indicated in his great work, “Recherches sur les Poissons Fossiles,” but with such modifications as the subsequent investigations of ichthyologists have rendered necessary. These modifications occur chiefly among the fishes of the older formations.

Although the Mendip Hills have received a large share of attention from geologists since the beginning of the present century, and particularly from Buckland and Conybeare, Weaver, De la Beche, Ramsay, and Moore, there are still many points of great interest that require to be worked out.

In the Geological Magazine, Vol. VII., p. 260, PI. VII., Figs. 2–5, we published a description, by Prof. de Koninck, of a new British Cystidean, which the author named Placocystites Forbesianus. We called attention in a footnote (op. cit., p. 261) to the probability of Prof. de Koninck's Cystidean being the same as Mr. Billings's Ateleocystites Huxleyi; but as we had not seen the Canadian specimen upon which the genus was founded, we abstained from speaking very positively as to their identity. We, however, prepared a sketch of Placocystites, which we forwarded by Sir William Logan, who kindly undertook to submit it to Mr. Billings, in order to obtain his opinion thereon. We have been favoured with the subjoined letter, which has, however, been accidentally mislaid, and so for a time delayed in publication, for which we beg to apologize.

Between the mountains of North Wales and the sea, occur two terraces, an upper composed of Boulder-day sloping towards the sea, and a lower, consisting of peat and alluvium, but little removed above high-water mark, running far inland, wherebroad valleys like the Vale of Clwyd breach the coast, and where rocky headlands jut into the sea, as the Great and LittleOrmes Heads. The two terraces are almost entirely denuded away, but often the lower one has alone suffered, as between Penmaen Bach and Penmaen Mawr, where a bay in the rocks, so to speak, is filled up with Upper Boulder-clay. It is quite evident that before denudation of the coast took place, the peat plain had a far greater extension than at present, which is proved by the foot of the occurrence of peat and a submarine forest at Rhyl, in borings in the Dee, and around the whole coasts of Cheshire, Lancashire, and southern Cumberland. It is also evident that considerable denudation of Glacial beds had taken place before the period of the old forests, and that the sea-ward prolongations of these beds, which themselves rested on an old sea-bottom, had been denuded away, and that a great plain, or series of plains, formed much of what is now the Irish Sea, before the forests came into existence; the lower terrace now fringing the coasts being the landward edge of this plain. It is nowhere better seen than in the Birket plain, forming the northern portion of the Hundred of Wirral, in North Cheshire. It is bounded to the south by an old pre-Glacial cliff, which abruptly terminates the northerly prolongation of all the numerous longitudinal valleys running with the strike of the Triassic rocks, of which this district is composed, each valley having a steep escarpment facing the west, as described by Professor Hull and myself.

Boulder-scars.—From Maryport to Parkgate, the E. coast of the Irish Sea at intervals exhibits accumulations or concentrations of large boulders, which are locally called scars. They may be seen in all stages of formation, from the denudational area, where they are in course of being left by the washing away of the clayey matrix, to the depositional area, where they have become half-covered with recent sand and shingle. In many places (as between Seascale and near Silecroft) there are so many boulders within a small area as to show that a considerable thickness of the clay must have been removed. With the exception of having tumbled down as the cliffs were undermined and worn back by the sea, many of the boulders may still rest nearly in the positions they occupied in the clay, but (as is evidenced on the coast at Parkgate) others, up to a great diameter, may have been shifted horizontally. Some of the scars exist where the Boulder-clay would appear to have risen up into ridges or mounds, as no clay is now found opposite to them at the base of the sea-cliff. Others are clay and boulder plateaux, visibly connected with the cliff-line. Most of the scars, I believe, are remnants of the great Lower Brown Boulder-clay. The most conspicuous boulder in the scars S.W. of Bootle, is Eskdale-fell granite, accompanied by a little Criffell granite, and a great number of the usual felspathic erratics.

In the July Number of the Geological Magazine a well-known geologist has endeavoured to prove the existenceof sands of the Chillesford age in the Crag Pits near Butley, referring more especially to that on the Neutral Farm, nearthe Oyster Inn; and as I cannot agree with this opinion, I venture to lay before the readers of the Magazine some of the notes upon which I ground my dissent.

It appears evident from the history of the metamorphic, granitoid, and granitic rocks of Scotland, written exactly halfa century ago by MacCulloch, that those rocks are very similar to rocks of the same classes in West Galway, Ireland. This acute observer evidently examined the Scotch rocks most minutely, as the groups, sub-groups, and varieties of his “primary rocks” are carefully classed and described. Still, however, his arrangement seems to require modification, as many of the rocks he has put among his granites seem not to be true granites, but rather granitoid rocks, due to the metamorphism of igneous rocks.

Having formed one of a party of sixteen, who have lately further explored the recently discovered caverns at Stainton, notices of which have appeared in the Times and other journals, I wish to furnish a few details of the exploration, which may possibly prove interesting. The caverns are in the Carboniferous Limestone formation, and situated at a point one mile and a quarter south-east of the Dalton station of the Furness Railway, Lancashire.

During the years 1866 and 1867 considerable discussion took place through the medium of this Journal on the question ofthe existence of dislocations, or faults, in Glacial Drift. As I believe no communication has appeared since the latter year in these columns on that subject, it may not be altogether uninteresting to your readers if I briefly refer to a clear and unmistakeable example of faulted drift which recently came under my observation at a ballast pit close to the Stockport Railway Station. At the time of my first visit, about three months ago, my object being to search for traces of marine shells in the sand, the several details of the section were exhibited with remarkable distinctness, the action of the weather having brought out the several lines of bedding and fracture as sharply as though they had been produced in a body of compact Sandstone; indeed, so exact was the resemblance in that respect that at a short distance it would have been difficult to believe that such was not the fact. Unfortunately, since that time, a quantity of sand has been removed from the face of the pit, thereby partially obliterating the details; the principal features, nevertheless, were easily discernible a few weeks ago, when I last visited the spot.

For the last three summers we have devoted the greater part of our leisure time to the examination of the Silurian Rocks that lie more immediately between the Moorfoot Hills and the English border. Our investigations have been attended with a fair amount of success, and we thought that a short summary of what we have accomplished would not be wholly uninteresting to the Geological Section. As these old Silurian strata of the South of Scotland have only been once alluded to in the papers already read at the Meeting—namely, by the Chairman in his eloquent address—we may be pardoned if we say a few preliminary words concerning them.

In the early part of this year I paid a visit to the north-western part of Donegal. My stay was short and my time too much taken up with other matters to allow of detailed geological work; but there were two things that at once attracted the attention of the most casual observer, the bedded character of the granite, and the traces of former wide-spread glaciation. To these I gave such time as I could, and on my return threw my notes into a paper which was read before the Geological Society of London. On seeing my paper, Mr. E. H. Scott had the kindness to send me copies of two papers of his own and of a report by himself, Sir E. Griffith, and Professor Haughton, on the Donegal Granites, in which, among other matters, the bedded character of these rocks was pointed out.

The Graptolites for which the name Dicellograpsus is here proposed are usually included in the genus Didymograpsus, which is thus made to comprise two groups of species which are not only generically distinct, but belong to entirely different sections of the Graptolite family, the species properly belonging to Didymograpsus (D. Murchisoni for example) having hydrothecæ similar to those of Graptolithus, while the species erroneously included in the genus (D. Forchhammeri and others) have hydrothecæ of the type of Climacograptus. This was first pointed out by Prof. James Hall. In his “Graptolites of the Quebec Group” (p. 57) he removed these species from Didymograpsus, and placed them in his new genus Dicranograptus; the species previously known as Diplograpsus ramosus being considered the type of the genus. To this species, and to another then first described, the genus was afterwards restricted by Mr. Carruthers, the remaining species being again included in Didymograpsus. Though fully agreeing with Mr. Carruthers in thus restricting Dicranograptus, I cannot consider the species removed from it as having any alliance to Didymograpsus.

Having had my attention drawn to a communication from H. W. Bristow, Esq., F.R.S., District Surveyor of the Geological Survey of England and Wales, which appeared in the Wells Journal of 12th October, and which relates how he came upon a shaft (with steam-engine, etc., in full operation) that was being sunk for Coal about three-quarters of a mile North of Easton, in Somersetshire, and which shaft penetrated the Old Red Sandstone to a depth of 112 yards, starting at a point from 3,000 to 4,000 feet below the horizon of the lowest strata of the true Coal-measures, I think it not undesirable to make known the fact of an as unwise and hopeless search for Coal in Northamptonshire, at a point probably more removed vertically, but in the opposite direction, from any strata in which Coal wonld be likely to be found.

The paper of Mr. Hull, “On the General Relations of the Drift Deposits of Ireland to those of Great Britain,” in the July number of the Geological Magazine, induces me to recur to one by myself on the Sequence of the Glacial Beds, Vol. VII p. 17 of the same Magazine.