In opposition to the views enunciated by Lyell and the older geologists, and until now generally accepted by those who have made physical geology a study, an opinion is gaining ground that “generally speaking the great continents and great ocean basins have occupied their present positions through all geological time;” that they are, though subject to oscillations of level, permanent depressions and elevations produced by the gradual diminution of the earth's diameter through loss of heat and consequent sinking in of the rigid crust.

Description.—Specimen from the Coralline Oolite of Pickering (Leckenby Collection).

Shell moderately elongate, conical, solid. Spire formed of an angle very nearly regular. The whorls are numerous and of moderate height. The posterior whorls in this specimen have suffered from abrasion. They are nearly flat, and the ornaments were apparently similar to those in the central part of the shell. The ornaments on the anterior whorls, if ever they existed, are for the most part obliterated, but the nodular character of the rim at the base of each whorl is still shown; these whorls are moderately excavated. The ornaments on the portions preserved in the centre are as follows. Each whorl is slightly depressed in the middle, and closely fitted on to the next by a raised nodular rim: that rim which is at the base of each whorl is by far the most nodular. Five transverse rows of granulations, the three centre ones being the strongest, fill up the space between the rims.

The Limestones of the Yorkshire Oolites long ago attracted the attention of collectors from the remarkable beauty of some of the fossils which are preserved in them. We need hardly go back so far as the days of Lister and his lapides Judaici, but the Scarborough Catalogue, published in 1816, may arrest our attention for a moment.

Twenty-two years ago, Mr. E. Billings, F.G.S., the late excellent palæontologist to the Geological Survey of Canada, completed and published Decade iii. of his “Figures and Descriptions of Canadian Organic Remains” (Montreal, 1858), containing an admirable monograph on “the Cystideæ of the Lower Silurian Rocks of Canada,” wherein (at pp. 72–74) he gives a clear and concise account of a very extraordinary fossil Cystidean, with a very poor woodcut figure of one side, the plates of which he clearly describes. To this fossil he gave the name of Ateleocystites Huxleyi. The specimen was obtained from the Trenton Limestone, near Ottawa, Canada. (See our Plate VI. Fig. 1.)

I wish in the present paper to draw attention to one aspect of the Whin Sill specially, viz. its aspect as an assimilater, and other interesting points connected with it I shall only mention incidentally, as they may arise during our investigation of this aspect.

During the past twelve months I have devoted much time to the careful study of those questions that relate to the probable source of derivation of the sandstone and quartzite boulders or “pebbles” that were drifted and accumulated in the neighbourhood of Budleigh Salterton by “Bunter” waters. The detailed results of my investigations will appear in my forthcoming Devonian Supplement. Cornwall and North Devon having been pointed at, as a probable source of derivation, I considered it necessary to study the rocks and fossils that exist in those portions of Great Britain, as well as those that occur in Normandy and Brittany, on the other side of the Channel.

In September, 1875, Decade II. Vol. II. p. 394, of this Magazine, I was enabled, after having previously described them in detail, to group all the known British Cretaccous Aporrhaidæ together into four genera; and in March, 1876, I added a fifth genus.

The following notes have been made during a few weeks' holiday in the Isle of Man, and my special object is to notice those points which have a bearing upon the geology and physical history of the neighbouring Cumberland mountains. For many years I have, from time to time, looked across to the hills of Mona's Isle, regarding them as a portion of the Cumbrian group standing aloof from their brethren, and often have I wished to carry my hammer amongst them. My wish has at last been fulfilled, but the bad weather of the coldest of summers has prevented the observations made being as full as I had intended. Such as they are I offer them.

On a visit to Devonshire, in August, 1879, I was conducted, by my friend, Mr. John Edward Lee, F.G.S., of Torquay, to a recently discovered locality at Lower Dunscombe, near Chudleigh, in which large Goniatites occur in considerable numbers in a bed of red limestone. On the slope of a chain of hills, not far from one of the farm-houses belonging to Lord Clifford, there is a ruined quarry, in which a vertical face of limestone is exposed.

Bibliography, etc.—This is just one of those cases where it is so difficult to choose between accepting names for forms which, though allied, are distinct, or simply lumping all the forms together under one specific designation, which does not exactly fit any of them. Objections more or less valid may be urged against either course, and some might be disposed to cut the Gordian knot by making new species all round. Buvignier went very closely into the varieties of the Corallian Cerithia. He points out that the true C. limœforme of Rœmer occurs rather higher than the Coral Rag, viz. in the “calcaire à astartes,” to which it is restricted. It is characterized by three rows of transverse granulations, just as shown in Rœmer’s enlarged figure, though at times a fourth or even a fifth very faint one is developed. It is difficult to say of what value these refinements may be, but certainly C. limœforme, as thus restricted, cannot be exactly identified in the Corallian of Yorkshire, where its place is occupied by forms slightly different, though in our collections they have been generally lumped together under the heading C. limœforme, Rœmer.

Whatever may be the precise biological value of this genus or subgenus as distinct from Purpura, it forms a remarkable group, limited, according to our present knowledge, both in time and space. Of the conditions favourable to its development we only obtain glimpses here and there. In the Coral Rag of Yorkshire one would say that the genus displays a remarkable tendency to variability within certain limits, so much so that almost every specimen found in anything like a decent state of preservation differs in some point of ornament: hence the extreme difficulty of specific arrangement. One might almost suppose that, like the Ammonite, the genus having worked out the limits of possible change, flourished within a short period only, and speedily became extinct.

A New and interesting species of Trilobite having lately been obtained by Professor A. Liversidge, F.C.S., F.G.S., of the University of Sydney, in the Silurian rocks of Bombala, New South Wales, and forwarded to my colleague, Mr. R. Etheridge, jun., F.G.S., with a series of other Palæozoic fossils, from Australia, it has been obligingly placed in my hands for description.

It is not proposed to discuss the merits of the generic name applied to a group of Univalves so characteristic of and so abundant in the Jurassic rocks. Melania, Eulima, and Chemnitzia have each of them served in turn, and in adopting Chemnitzia after D'Orbigny, the late Dr. S. P. Woodward observed that the “Melaniœ” of the Secondary rocks are provisionally referred to this genus. Pictet and Campiche include the Chemnitziœ and Phasianellœ of the Oolites in one genus Psendomelania, thus preserving to a certain extent the old generic appellation.

Under the name of Caunopora placenta Prof. Phillips described a fossil which is very common in the Devonian Limestone of South Devon, and which Mr. Lonsdale had described before as Coscinopora placenta. It forms amorphous or spheroidal masses composed of thin concentric laminæ, and perforated by small flexuous or vermiform tubuli.

In my first communication on the Carnivora I gave, at the commencement, a list of all the species said to have been found in on thethe “ Forest Bed,” and then at the end a corrected list. The same course will be followed in the present instance, so as to show at a glance, those species which have been removed and those which have been added to the list.

Two papers, presented by Prof. Hughes to the Geological Society during the last twelve months, call for some comment from myself, as in many respects they controvert, directly or indirectly, opinions which I have expressed before the same Society. In the debates which followed I objected to the imperfect evidence on which these criticisms were founded; and as the author repudiated with some warmth my right to demand that conclusions founded not only on field work, but also on microscopic study, should not be assailed from the former point of view alone, I will venture to state the reasons why I so did, and intend so to do on any future occasion that may arise.

Nearly every text-book on geology speaks of the heat which has been lost by the earth, and the consequent contractions which have taken place upon its surface. The way in which all this has come about, however, is either not explained at all or else very imperfectly, and the difficulty experienced by any one endeavouring to find out what the conditions have been will be fully recognized by reference to the lengthy correspondence which was carried on in the columns of Nature (December, 1878, and January, 1879) between Mr. A. R. Wallace, Mr. O. Fisher, and others, upon this subject.

At the beginning of this century nothing whatever was known about the history of the Carnivora in the Eocene period. In 1825, in the second edition of his “Recherches sur les Ossements fossiles,” Cuvier described certain fossil bones from the Gypseous Series as belonging to a Carnivore allied to the Racoons and the Coatis. Ten years afterwards, having obtained a palate from the same beds, furnished with five teeth on one side and four on the other, he referred the palate, as well as the bones alluded to above, to a genus allied to Didelphis. De Blainville, in his “Osteographie,” founded on these bones a genus allied to the Badger, which he placed amongst the “Petits Ours” (Subursidæ), under the title of Taxotherium, while he referred the supposed Didelphoid teeth of Cuvier to a distinct genus, Pterodon, to which also he assigned a place in the same group.

Taking into account the large number of papers that have been published on the Glacial Deposits near Cromer, any further description may appear unnecessary; and it was with this impression that I commenced the systematic examination of the coast three years ago. Before long, however, I found that in many important points the actual facts do not support the accepted theories of the origin of the deposits; and having now made a thorough examination, I lay the results before the reader.

I have read with much interest Mr. Reid's paper on the Glacial Deposits of Cromer. It is a valuable contribution towards the elucidation of a difficult subject. I cannot, however, think that at present the mode of accumulation of glacial deposits is finally settled. The old people, among whom I count myself, used to consider these heterogeneous mixtures to have been dropped from floating-ice, or to have gone down, ice and all, to the bottom of the sea, when so much of the ice had been thawed that the mineral matter exceeded one-twentieth of the whole bulk. Now, however, many of the younger geologists, and especially those connected with the Survey, attribute much more importance to the action of great glaciers or ice-sheets, enveloping not only whole countries, but also filling up and advancing over what are at present sea-beds.