As a contribution to our knowledge of the formation of these very interesting “natural embankments of the sea,” I may point to a little bay in Anglesea, immediately westward of the Bryn Ddu Limestone quarries on the north-east coast of Anglesea, about two miles and a half westward of Puffin Island. This little bay is not more than about a furlong across, and may be roughly described as semicircular in form, lying nearly due west to east from point to point. From being in miniature as it were, the ridge can be readily studied, and it is very striking to see how, commencing in the westward as a beach, it gradually rises into a ridge having very steep sides. No less remarkable is the way in which the stones increase in size as the ridge does in height. At the west end it may be described as composed of Limestone pebbles, with here and there a boulder, while at the east end it is built up almost entirely of large limestone boulders and blocks, many containing from one to two cubic feet and some more. Intermixed there are boulders from the size of the closed hand and upwards. The larger blocks are sub-angular and rounded, and no doubt get gradually worn down smaller and rounder, until they become “boulders.” by being moved about, by the sea; but some on the other hand, being thrown over on to the back of the bank, cannot be further affected by the waves. In this ridge, as I have pointed out is the case with the Chesil Bank, the stones follow the law of the bank itself, the largest being collected to form the highest part of the bank, which in both occurs where the wave-action is most intense.

The remaining shells figured on Plate IV. do not belong to the Scalidæ, but to families considerably removed. The form next described undoubtedly belongs to the family of Aporrhaædce, the rest are Rissoidæ.

There is a peculiar band, full of Annelid borings, in the Gault of Kent, which does not appear to have been recorded in the papers on the Gault of Folkestone, by Mr. De Rance, in the Geol. Mag. 1868, Vol. V. p. 170, etc., and Mr. Price, Quart. Journ. Geol. Soc. 1874, vol. xxx. p. 344, etc. It may possibly, however, be one of the “hard bands” noticed in their sections, but not described in detail. In 1866 I collected some specimens of this Annelid Bed in a Gault pit, dug for brick- and tile-making, at Westwell Leacon, a mile and a half S.W. of Charing, Kent. It was about two inches thick, continuous across the pit, red in colour, with bluish pipings throughout in every direction; it was much harder than the blue clay above and below, and relatively heavy. There seemed to be only one band of it; and its fragments were picked out and thrown aside by the clay-diggers, who called it “Harper.”

Polypary slender, several inches in length, distal portion straight, proximal portion sharply recurved. Hydrothecæ 20 to 25 to the inch, in contact at their bases only; narrowing in the direction of the apertural portion, which is curled up into a rounded lobe.

Following up the notes which recently appeared on Cretaceous Aporrhaïdæ, I now propose to continue from time to time notes on other Cretaceous Gasteropoda. At present I have selected for illustration “Scalariform Shells.” The most recent papers which refer to this subject are witnesses how much revision of the genera and species is needed to which our British Cretaceous representatives of this type have been assigned. I first take the family of Scalidæ, and will, as briefly as possible, endeavour to recapitulate what is at present known of this family.

Upper Silurian.—At the close of the Lower Silurian, as already stated, changes of considerable importance took place in some of the areas which had undergone depression. The sea-bottom was now raised in parts of Western Europe, and in North America, and islands of some extent formed. In Europe the most important were those in North Wales, Shropshire, Cumberland, the South of Scotland, and in Nassau. It is probable also that one or more extended along Southern Europe, from Portugal into Spain, etc., but the evidence concerning this is as yet imperfect. In America, according to Logan, Dana, etc., the principal parts raised at this time were the Green Mountain regions, and the ridge extending from Lake Erie over Cincinnati into Tennessee. These American ridges appear to have been raised to a great height, and to have remained afterwards in part dry land, even to the close of the Palœozoic. The islands in Europe were raised only to a small height above water-level, and were probably all again submerged by the close of the Upper Silurian.

The arguments I endeavoured to outline in the June Number of the Geological Magazine have evidently been partly misunderstood by at least one gentleman whose opinion is valuable, and I desire therefore to illustrate them somewhat further.

In the Report of the British Association for 1874 will be found the abstract of a paper on the Age and Mode of Formation of Lough Neagh, with a description of the Pliocene clays which form an ancient and extensive delta at its southern extremity. At the time I penned the paper in question, although I was perfectly satisfied from cumulative circumstantial evidence that the clays were of much more recent date than the Miocene Basalt which surrounds the lake on three sides, I had no actual proof to bring forward—the junction of the basalt and the clay beds being nowhere visible, so far as I had had an opportunity of examining the district, this comprising all the shores of the Lough, with the exception of a small corner near Crumlin; and it was therefore necessary to state, even at the risk of tediousness, the reasons why the clays must be considered to be the uppermost, and to be of Pliocene age.

1. Succession of Silurian Rocks in the South of Scotland.—The oldest fossiliferous strata yet detected in the Silurian district of the South of Scotland are the dark Graptolitic shales forming the well-known Moffat Series. The total thickness of this group is under 600 feet, but it is nevertheless capable of separation into three very distinct palæontological divisions, each characterized by a large proportion of peculiar fossils. The first of these divisions is of Llandeilo age, the second represents a portion of the Bala formation of North Wales, and the third, or Birkhill division, appertains, at least in part, to the epoch of the Lower Llandovery.

There is a fine exposure of the “Lower Greensand” in a railway cutting by Sandy Station on the G.N. and L. & N.W. Railways, presenting a nearly vertical section 50 or 60 feet in height. It consists almost entirely of clean sand, in parts falsebedded, and more or less coloured throughout by the presence of oxide of iron. The colour thus imparted to the sand varies from almost pure white, at the lower part, through shades of grey and yellow, to a deep rusty brown. There are here and there layers of hard ferruginous concretions in tabular, spherical, and many other forms, presenting a feature hitherto (so far as the writer is aware) unnoticed. This is a gradual passage from soft iron-stained sand to hard complete concretions, exhibiting the various stages in the process of their formation.

In the Geological Magazine for April, 1871, I attempted to account for the mode of occurrence of the masses of Carboniferous Limestone that are found in the midst of the Coal-measure country at Luckington and Vobster in Somersetshire, and I then drew a picture of a faulted and inverted anticlinal to explain the phenomena. Mr. McMurtrie, who has more recently re-opened the discussion on the subject, and in a friendly manner assailed my theory, again asserts that the Limestone masses “must in some way have been folded over” from the Mendip range. He has very clearly brought forward all the local facts that bear upon the question, and has represented in diagram the mode by which he would account for the position of these isolated areas of Carboniferous Limestone. No one is so familiar as is Mr. McMurtrie with the detailed structure of the Somersetshire Coal-field, and I look forward with great interest to the facts which he is enabled from time to time to bring forward; nevertheless I may be pardoned for still differing from his general conclusions, inasmuch as the facts at present made known appear to me neither to upset my own theory, nor to establish that advocated by Mr. McMurtrie. Indeed it is only due to him to observe that he does not consider the question as finally settled, although he brings forward facts which seem to him to militate against the theory I ventured to propose.

VI. Jura.—In all probability the strata which form the summit of the mountain north of Reindeer Valley in Saurie Hook belong to the Jurassic formation, which besides occupies a considerable extent on Spitzbergen, from the entrance of Ice Sound to Cape Agardh in Stor Fiord. To judge from the beds at the latter place, the only one that I know of which affords a comprehensive section of the different strata belonging to this formation, the Jurassic strata of Spitzbergen consist of—

Cretaceous Beds.—During our previous Expeditions we had not fallen in with any strata belonging to this period on Spitzbergen; but in the beginning of the Expedition of 1872 I had the good fortune to supply this missing link in the geology of Spitzbergen through the very unexpected discovery, in the immediate neighbourhood of the Taxodium strata at Cape Staratschin, of fossil plants, which had an unmistakable reference to the fossils which I brought home some years ago from Kome in Greenland (Lower Cretaceous). A closer examination by Professor Heer showed that this supposition was so far correct, inasmuch as the strata in question truly belonged to the Cretaceous series, though occupying a position more recent than the Kome strata in Greenland.

I Fear I must express my ideas very indistinctly, seeing that I am so frequently misunderstood by my critics. Quite recently a well-known American astronomer, in reviewing my book, “Climate and Time,” devotes nearly a dozen pages to the refuting of views most of which I have never held. And in the July Number of the Geological Magazine I am sorry to find a repetition of the same thing.

A Good deal of attention has been lately bestowed on the Raised Sea-beaches around the British Islands and the evidence afforded by them as to alterations in the level of the land. Some geologists seem to entertain the idea that such beaches were originally accumulated on horizontal lines; and they have drawn the conclusion, that when one portion is found to be higher than another, it necessarily indicates an uneven rise in the surface of the earth. This idea, however, is erroneous; and the object of this paper is to prove, from the data supplied by the Ordnance Survey and the Admiralty Charts, that the littoral deposits at present accumulating around Ireland are being formed at varying levels.