The occurrence of plant-remains in the Silurian and Cambrian rocks is a subject of great interest, but one which has not hitherto been sufficiently investigated. Many supposed plants have been described by Emmons, Hall, Billings, and Dawson, from the older Palæozoic rocks of North America, and little doubt can be entertained of the vegetable nature of some even of the most ancient of these. Many, however, as believed by Professor E. Forbes and Mr. Salter, are certainly referable to the tracks or burrows of marine animals. More recently the Cambrian rocks of Sweden have yielded to the researches of Torell and Linnarsson some remarkable impressions and casts of fossils, which are believed to be of a vegetable nature (Geol. Mag., September, Vol. VI., p. 393, Plates XI., XII., and XIII.). In Britain there is not, as far as I am aware, any instance of the occurrence of plant-remains in deposits of Lower Silurian age, as to the nature of which all authorities are agreed. The Oldhamia of the Cambrian rocks is believed by Mr. Salter to be a plant, but good authorities would place it either amongst the Polyzoa or Hydrozoa. The Cruziana semiplicata of the Lingula Flags has often been assigned to the Fucoids, but it is believed by Mr. Salter to be “the filled-up burrow of a marine worm” (Mem. Gaol. Survey, vol. iii., p. 248). Long ago Professor McCoy described from the Skiddaw slates (lowest Llandeilo) certain fossils which he believed to be fucoids (Quart. Journ. Geol. Soc., vol. iv., p. 223, and Pal. Foss., pl. i. A). After studying a large number of specimens, however, I have been compelled to come to the conclusion, held by Mr. Salter and Professor Harkness, that these fossils (viz. Palæochorda major, P. minor, and Chondrites acutangulus) are truly referable to the action of marine worms. Within the last few years, however, I have obtained from the Skiddaw Slates several fossils, which certainly do not admit of being explained in this manner, though I would not go so far as to assert that they are unquestionably plants. The age of the deposit in which they occur renders them, at any rate—whatever their true nature may be—of sufficient interest to merit a short description.

Allow me to call attention of your readers to an investigation which promises to be of considerable geological importance, and which might be pursued in many places without any difficulty—I mean the determination of the quantity of sediment carried down to the sea by rivers.

Some portions of the Lancashire coast in the Furness district give evidence of considerable changes of level since the first elevation of the Glacial deposits. The Boulder-clay formation of Cumberland and Lancashire exhibits a well-marked subdivision into a lowertough blue Boulder-clay, overlain, apparently on its eroded surface, by a redder silty clay of more variable composition. The same subdivision holds good along the coast of N. Wales; but I cannot satisfy myself that it can be definitely correlated with the succession of the Glacial series of the Norfolk and Suffolk coasts, or that the lower tough blue Clay can be traced inland much above highwater level.

The existence of Post-pliocene deposits in this neighbourhood has until lately been quite unknown, nothing of the kind having been detected either by the Geological Survey or subsequent observers. However, in tlie winter of 1866, a small section was exposed in a brick-field situated on a low rising-ground at the first milestone out of Shaftesbtiry towards Gillingham, and known as Hawkers' Hill. The clay here dug for brickmaking is Kimmeridge, presenting fossilized bones of the Pliosaurus and Icthyosaurus, and very friable remains of an Ammonite, etc. The attention of the writer was first attracted to the Drift on observing, above part of the Kimmeridge clay, a thin section of soil of an ochreous tint due to oxide of iron, and somewhat resembling the loose stratum of chert and sand which caps the neighbouring Green-sand rock. He learnt on inquiring of the labourers that they had recently found some large bones in this deposit, but thinking them of no use they had wheeled them off with the rubbish, in which they then lay, efiectually re-buried. Much interested at this announcement, he induced the men again to remove the rubbish, and found that the bones were some vertebræ of a large mammalian animal, together with fragments of the ribs and leg-bones. They were, of course, not at all fossilized, and their original weak state had been sadly aggravated by a second burial and disinterment. Nothing more was turned out that winter, and it was not until the end of 1867, that digging was resumed. Further portions of the same skeleton were now found, including another instalment of vertebræ, and portions of the skull and jaws. With the latter were several teeth in a suffciently entire state to show that the creature weis undoubtedly a Hippopotamus; numerous fragments of the tusks affording further proof of this. The writer now frequently visited and watched “the diggings,” and after a short time two horn-cores, considerable portions of the skull, and some fragments of the leg-bones of Bison priscus of unusual size came to light. The more perfect horn-core is 18 inches long and 14: inches in diameter at the base.

The superficial deposits of the Co. of Wexford, containing a rich marine fauna, have been referred to in Professor E. Forbes's Memoir on “The Geological Relations of the existing Fauna and Flora of the British Isles.”

Geology.—Stated roughly, the geology of the Department of Finistère may be said to consist of two masses of granite, one to the north and one to the south, enclosing between them nearly the whole of the sedimentary rocks of the district. These consist of Cambrian slates and gneiss, Lower, Middle, and Upper Silurian slates and grits, and very small and unimportant patches of Upper Carboniferous shales. The entire mass of these deposits has an east and west direction, and occupies the central part of the Department.

Having had our attention directed by Mr. Barkas's paper to the specimens of this genus in the National Collection, and compared Mr. Barkas's figures with Mr. T. Atthey's description of Ctenodus tuberculatus [see “Annals and Magazine of Natural History” (4th series), Feb. 1868 (p. 83)]; Mr. W. Davies having also kindly pointed out to us a small but very perfect palatal tooth (see Plate IX. Fig. 3), probably from the Coal-measures of Carluke (from the collection of the late Mr. Alexander Bryson of Edinburgh), closely agreeing with Mr. Atthey's description in all its characters; we have thought it well deserving of a place in our Plate.

In the former notes “On the growth of soil,” I omitted to speak of the labours of the ants—these workers, although such pigmys in this country, and, therefore, compared with the earth-worms, less capable, individually, of work, are so numerous and energetic, that in the special places to which they resort, their yearly work is much more conspicuous than the annual worm-work; but the animals operate in different places, for while the earth-worm luxuriates in rich highly-cultivated land, the hill-building-ant loves a dry, sandy or peaty soil. In the spring the ants may be observed beginning their work, and from that time they carry on their operations all through the summer, to the late autumn, or early winter. On a moor they raise hillocks scattered promiscuously about over the ground, getting closer and closer together as the colonies increase. But where the ants are most useful is in places where crags and large stones are mixed up with patches of sandy peat. In such a locality they will always build on a rock, the foundation of their habitation being at its junction with the soil. These ants seldom raise their structures as high as the moorland ants, but they make up in extent for absence in height, and by this means the rocks are gradually covered with soil and vegetation; for, on account of the season of the year at which they build, the growth of the plants keeps pace with the formation of the ant-soil, and protects it in a great measure from “Meteoric abrasion.” During the winter, however, the shape of the ant-hills is somewhat modified, but the matted roots of the plants preserve the major part of the soil which will thus remain, forming an envelope for the rock.

The modern method of determining the amount of heat effects in absolute measure is no doubt destined to cast new light on all questions connected with climate, as it has done and is still doing in every department of physics where energy under the form of heat is the phenomenon under consideration.

The importance of experiments and investigations such as those recorded by the Rev. J. D. La Touche, in the Geological Magazine for April, can hardly be over-estimated from a geological point of view, and, if carried on in numerous districts and for a sufficient length of time, would furnish data with which, and a basis from which, future calculations as to the rate of denudation at present going on over the land surface of the globe might be esti- mated. For it cannot be denied that at present there is a laxness in the method of computation as regards the rate and amount of degradation both for past and present epochs which ill accords with the ultimate end and aim of all scientific pursuits, viz., truth. Each one taking a rate which seems most to confirm his own particular tenets, as, for instance, the different rates at which the river Niagara has out its way back from Queenstown Heights to the present situa- tion of the Tails. It has been taken as three feet, one foot, six inches, and one inch per annum, by different computators. Now I do not say that investigations on the river action of the period in which we live will clear up all such anomalies, because these obser- vations will be of more service in estimating the future rate of the wearing down of the materials composing the land than that of the past, as there would always be the difficulty of ascertaining with precision the volume and velocity of the rivers, and the different elevations at which the land was situated at the particular era under consideration; still it would be a fulcrum on which we might rest the lever of analogy, and raise many questions at present resting in obscurity and doubt into light and certainty.

It is not unusual in drift deposits, banked on hill slopes, to find a deep cut occupied by a very minute stream. These outs or ravines are supposed to be due to the streams; having been excavated by them in the banks of drift. If a ravine of this class is formed in one of the older drifts—namely, the Boulder-clay-drift or the Moraine-drift—it must apparently have been cut by a stream, but much of the drift banked on hill slopes is quite recent; that is formed by meteoric abrasion, and being added to at the present day. In these recent drifts, ravines are of common occurrence, and I would suggest that, instead of the stream cutting its ravine, meteoric abrasion has heaped up the banks, and the only action capable of being done by such a stream, is to keep its channel clear. Such accumulations of drift are very frequent in association with Maums, or connecting gaps across mountain-ranges, and there are always ravines in the banks,—yet by no arrangement of the water-supply, could streams be formed that would have the power to excavate them. In the accompanying sketch of Maumgeeha, Yar-Connaught, there is a maum, below which is a recent drift-bank with a ravine and its accompanying stream. None of the surface drainage of the hills on either side of the maum can get into the stream, it being fed by a spring, while the surface drainage of the mountains flows as represented by the arrows, and yearly the shed from the hills adds to the height of the banks.

As several papers by Mr. David Forbes and Mr. Sorby have probably by this time induced a few Geologists to turn their attention to the importance of a microscopical examination of rocks and minerals, it may interest some of your readers to know that the application of this method of research has just lead to a rather interesting discovery.

Among a great number of specimens of Crinoidea from the Mountain Limestone collected by me during several years past, there are many parts of columns which shew an enlargement of the diameter or bulging similar to that described by Miller as representing “the remedial effect of calcareous secretion in repairing an injury of the joints of the stem,” and some few portions have occurred having the appearance of a small column rising from the centre of a larger one as shewn in Woodcut fig. 1.

Although the subject of this paper has already been discussed in detail, yet, as this has been done from a medical rather than from a geological point of view, it may be well that the chief facts of the case, the method of investigation followed, and the conclusions come to, should be brought before the Geological Society; for the Society will not fail to have an interest in noting what a practical bearing our science has on the health, as it has long been known to have on the wealth, of mankind.

In my former note on the discovery of Bos primigenius in the Lower Boulder-clay, I stated that there was some “slight twisting and confusion” of the stratified deposits below the superincumbent Boulder-clay, which might have been caused by the pressure of glacier-ice. As the crumpling of sandi clay, and gravel, below Till, is by no means uncommon, and has frequently been described, I did not think it worth while at the time to give any drawing of the contortions exposed in the new railway cutting. But some geological friends having asked me about the character of these crumplings, it may not be out of place if I now add a few particulars. "When my former note was written the disturbed portions of the stratified deposits were not very well exposed, and consequently I did not in my communication lay much stress upon their occurrence, although I had little doubt as to their origin. Upon visiting the section some weeks later, however, I found the crumplings well displayed. In October last I saw them again, in company with my brother, Mr. A. Geikie. By that time the section had been still better developed, and the annexed sketch of a portion of the crumpled clays was made.

The district to which attention is directed is situated in the centre and the most elevated part of Great Britain, which is thickly inhabited by an industrial population, many of whom are occupied in the working of Lead-mines. The Agent's house of the Beaumont Mines is at an elevation of 1400 feet above the sea, Kilhope Law rises 2206, while Crossfell (capped by Millstone Grit) attains a height of 2901 feet; Dufton Pike 1575 feet, and the Cheviots 2676 feet, the three counties of Northumberland, Cumberland, and Durham meeting at Rampgill Head; Durham, Yorkshire, and Westmoreland at Cauldron Snout. This elevated district, bounded on the east by the Tyne and Wear Coal-field, and on the west by the Whitehaven field, chiefly consists of the Carboniferous rocks, and presents varied physical features. The Penine chain, of which Crossfell is a part, extends from the borders of Scotland to Derbyshire, and from its westerly trend it forms the watershed, whence on the east side fall the waters of the Tyne, Wear, and the Tees. The country presents a varied aspect; to the east are broad low plains, succeeded by rolling hills and dreary elevated moors, followed by a more hilly and more rugged district, rising gradually on the east side of the Penine chain, and descending more steeply on the western side. These, together with the character of the rocks, influence the vegetation of the country, as shown by the “basset” of the Great Limestone, which forms almost the boundary of cultivated land and human habitations. Above it (as Mr. Sopwith observes) are more or less brown and dreary moors, and below it the hill-sides present a green surface and flowery meadows. The counties of Northumberland and Durham occupy about 2905 square miles, three quarters of which belong to the Carboniferous strata.

Attention having been drawn of late to the “Northampton Sand” by the able papers of Mr. George Maw and Mr. Judd, and by the discussions which arose upon them, and to the Oolitic beds of Northamptonshire generally, by the too concentrated article (so rich in information) by Professor Morris, in the Geological Magazine for March, and by a letter from the Rev. P. B. Brodie elicited thereby in the May number, I venture to offer the following provisional statement as to the Oolitic strata in the neighbourhood of Northampton, and the order in which they occur, purposing at some future time to write more fully upon them, to enumerate the palæontological contents of each bed, and to endeavour to correlate the Northampton series with those occurring in the more northerly parts of the county and around Stamford.

In the Geological Magazine of December, 1868, appears an article on this subject by Mr. J. R. Gregory, declaring the whole story of the Cape diamond discovery to be “false,” “an imposture,” “a bubble scheme,” got up to promote the expenditure of capital in in searching for this precious substance in the colony; and stating that, from the geological character of the district which he had lately very carefully and thioroughly examined, it was impossible that diamonds had been or could ever be found there.

Sixteen years have now passed since Mr. Davidson's Monograph of the British Secondary Brachiopoda appeared, and as numerous additions have been made from time to time, it is my present object to collate the scattered records of the additional species, and to supplement such information by notices of new or little known forms.