Of the various geological evidences inferring a vast duration of the existing contour and conditions of surface since the latest marine submergence, there is, perhaps, none more striking than the accumulation of great masses of Tufa charged with recent organic remains.

The beautiful crustacean, forming the subject of this paper, which is represented of the natural size in the accompanying plate, was obtained by Mr. J. W. Marder, from the Lower Lias of Lyme Regis, in Dorsetshire.

As a slight contribution to the elucidation of questions of denudation, and at the same time an exemplification of the application of mathematics to a geological problem, I send the following:

Noticing a lofty chalk cliff, forming the face of an old quarry in the neighbourhood of Lewes, I remarked that the action of the weather upon the surface was to disintegrate it equally all over, so that the face of the quarry remained vertical, while the stuff that fell down formed a talus, whose surface was approximately a plane, inclined to the horizon at that particular angle at which such materials will stand. The question then occurred to my mind— What will be the profile of the solid chalk behind the talus?.

A small quantity of a highly ferruginous water was lately given to me for analysis by my friend and former colleague, Dr. John Bayldon. He had collected the sample himself at the spring in Mimosa-Dale, Uitenhage, South Africa, where also he had obtained specimens of the iron-salts which are freely deposited by the chaly-beate waters.

The next operculated species which claims our attention is the Calceola Gotlandica of F. Roemer. This species has been removed from the class Brachiopoda in a list of the Upper Silurian Brachiopods which I published in 1860. I now give my reasons for so doing (then but briefly indicated).

Among the many beautiful fossils from the Silurian strata of Bohemia, obtained by M. J. Barrande, there have been discovered numerous detached spines, measuring from six seven inches in length, which, from their resembalance to the genus Leptocheles of M'Coy, have received the MS. name of Leptocheles Bohemicus (Barr).

It was publicly stated not long since that of all the Silurian strata there were no two so closely connected as the Liandilo and Caradoc groups. At the time this seemed a bold assertion, considering the great number of genera which were then thought to originate in the latter, not being known in the former. Some new forms, however, that have lately come to light from the Llandilo flags, shoe the connection between the two strata to be closer than it formerly appeared.

My knowledge and observation of facts are neither of them sufficient to enable me to determine the mode of deposit of these blocks in their present sites; probably they may have been glacially trnasported, at the same time with the gravel, to the places where they are now found; or, possibly, they, or some of them, may have been swept away from their original localities in the Tertiary formation, by a flood, or floods, general or partial.

The Flint and Stone implements sometimes found in this and other countries seem to form a sort of connecting link between geological and human antiquity; they are certainly the work of man, and they may possibly be older than the invention of metallurgy, and nearly coeval with the human race: it becomes therefore a matter of some interest to determine whether and to what extent the use of stone implements may have been contemporary with that of metals; and the references below given will, it is hoped, assist in elucidating this question.

1. The brown Boulder-clay corresponds with the brown Clay of the Eastern counties, and is oldest.

2. Then the hill gravel, the blue Boulder-clay, and perhaps the shell bed of March corresponds to the contorted drift.

3. As elevation progressed, the Fenlands would become one great fiord, ramifying at the Cambridge end up the southern valleys in the Chalk. First the coarse gravels of low levels were formed, and finally, during a long period—for the flints are wonderfully worn—the fine gravel of the plains. After which the country was elevated, and the sea denuded the superficial beds and retired. This corresponds to the Upper Boulder-clay and coarse gravel of the Norfolk section.

4. Now rivers cut their channels, and there commenced luxuriant vegetable growth, which corresponds with the excavation of the Mundesley river and the Mundesley peat.

5. Then a depression, during which was formed the Buttery-clay the Fens. This corresponds with the Upper Sands and Gravel of Mundesley.

6. And, finally, comes the second peat and the present state of nature.

I believe this succession is true for a far larger area than the Fenlands, perhaps for all Great Britain.

The plate containing the figures of the Polyzoa here described was prepared some years since by Mr. J. De Carle Sowerby, but has never been published, and no description of the fossils themselves has as yet been given. I have, therefore, been requested by my friend Mr. Woodward to draw one up; and the specimens have been kindly placed in my hands by Mr. N. T. Wetherell for the purpose.

I cannot refrain from adding, as a supplement to my remarks upon the Raised Beaches in the Pas de Calais, a few rough notes upon a similar formation, examined by me some years since, in Birnbeck Cove, near Weston-super-Mare. The distance apart of the two localities may seem to render this association of the descriptions uncalled-for, but a similar feature in each case makes a comparison between them interesting.

It is attempted in the accompanying diagram (Plate II.) to exhibit, as clearly as is possible in a single section, the local chronological arrangement and position of the more remarkable Cretaceous deposits between Folkestone and Guildford, and also their probable correlation with the same series in the Isle of Wight and the vicinity of Lyme Regis. The diagram therefore represents an ideal section of the Cretaceous series from Folkestone in Kent to Lyme Regis in Dorsetshire, exhibiting at a glance the relative positions of the strata in the order of their deposition, but without allowing for variation in thickness or possible want of conformity in stratification.

Professor Steenstrup, some years ago, questioned the fact as to whether the Zoantharia tabulata and rugosa, included by him under the common name of “Cyathophylla,” might be considered as true polyps. MM. Edwards and Haime in framing those great subdivisions of their “Coralliaria,” remarked their striking dissimilarity from the other Actinozoa. Professor Agassiz, in his grand monograph on the Acalephæ of North America, considers these differences so important that henceforth all connection between the above-named groups and the Zoantharia aporosa and perforata will be impossible. But besides these peculiar characteristics of the Rugosa, such, for instance, as the compact imperforate structure of the calyx and septa (the septa originating from four primary ones), the absence of costæ, the strange septal fossæ in the bottom of the calyx, the processes resembling rootlets, the transverse floors or tabulæ in the interior, which often have a cellular or vesicular structure; there is another peculiarity as yet not much known.

Three minerals, Nephrite, Agalmatolite, and Steatite, are much used by the Chinese for small articles of ornamental sculpture. The examination of several oriental specimens of these substances in my collection has led to some interesting results.

I Should not have presumed to publish an opinion as to the geological position of the roacks of Casterton Low Fell without having examined the typical region of Coniston and Windermere, had not Mr. Woodward thought it desirable to notice the occurrence there of a species of Ceratiocaris and asked me to furnish him with a note on the bed from which I obtained it. Having therefore collected all the evidence I could in that Limited and complicated area, I now, with the permission of the Director of the Survery, send him some extracts from my notes, which may be of interest, as showing the character and relations of the rocks there seen.