each row, delineated in fig. 3. This distance the two ranks maintain to near their rear end, where they again slightly approximate. I have seldom seen a more effective and formidable array of laniary teeth in the jaws of a Sauroid Fish.

Of such a fish the bone, of which two views are given in Plate IV., from the same formation and locality, is part of the superior maxillary. From similarity of size; but more especially from the similarity of number, size, and arrangement of the laniary teeth; from the corresponding degree of antero-posterior compression of the base of the tooth, as shown in Plate IV., fig. 2; from the proportions of the enameled and cement-covered parts of the crown, and from the shape and degree of curvature thereof, so far as is shown in the least-mutilated teeth (Plate IV., fig. 1), I am disposed to refer this specimen to the same genus and species as the mandible (Plate V.). În one of the large maxillary teeth I found, on scraping away the cement, a slight depression on the outer side of the base, as in the antepenultimate tooth in fig. 1; but this is neither so deep or so constant as in Thlattodus. In both the upper and lower teeth of Ditaxiodus a large pulp-cavity remains, partly filled by a lighter-coloured matrix than the outside petrified clay, as shown at Plate IV., figs. 1 and 2.

Most probably the inner rank of small mandibular teeth were opposed by a similar rank of teeth on the palato-pterygoid jaws parallel with the maxillary rank of laniaries.

The figures in Plates IV. and V. are of the natural size, and are explained in the text. My best acknowledgements are due to Mr. Cunnington for this and former opportunities of adding to the facts of Paleontology.

EXPLANATION OF PLATES IV. AND V.

PLATE IV-Portion of superior maxillary bone and teeth of Ditaxiodus impar. Fig. 1. Outer side.

2. Alveolar surface.

PLATE V.-Portion of dentary element and teeth of lower jaw of Ditaxiodus impar. Fig. 1. Outer side and rank of teeth.

2. Inner side and rank of teeth.

3. Anterior or symphysial end.

4. Under view of part of the dentary.

IV. ON AN ANCIENT BEACH AND A SUBMERGED FOREST, NEAR

MR.

WISSANT.

By E. C. H. DAY, F.G.S.

(PLATE VII.)

R. PRESTWICH has, in two valuable papers, published by the Geological Society,' given a very detailed description of a raised beach and associated recent accumulations, upon the coast in the vicinity of Sangatte, a village about five miles from Calais. In the second of these papers, the author mentions that he proceeded

1 Quart. Journ. Geol. Soc., vol. vii., p. 274, 1851; and vol. xxi., p. 440, 1865.

round the headland called Cap Blanc-nez, for the purpose of ascertaining whether any traces of a similarly recent formation were to be observed in the bay of Wissant, and that his search, as far as he went, was fruitless; "but," he adds, "owing to the extent of the dunes around Wissant, such a beach might be entirely hidden by the sands."

During a recent trip to this locality, I was more fortunate than Mr. Prestwich, for after having first noticed the raised beach north of Cap Blanc-nez, I met with what appeared to me to be a second one beneath the Sand-dunes, above referred to, in the neighbourhood of Wissant; and, still more happily, I discovered, at low-water level of the adjoining shore, a striking example of a "submerged forest." Unfortunately, however, for the reader of this article, I was at that time unaware that these formations had escaped the notice of Mr. Prestwich, and as I was also more particularly interested in the examination of the underlying Secondary rocks, I did not pay such attention to the details of the more recent deposits as they deserve to have bestowed upon them. My object in laying the very scanty notes that I did make before geologists, is therefore only to draw their attention to the existence of these phenomena, and to suggest further enquiry into their characters and into the conclusions to which they seem to point, so that others may be induced to supply my deficiencies.

Before describing the formation near Wissant, I must beg the reader's attention to a few words upon that near Sangatte; premising, however, that my own notes amount to a mere summary of Mr. Prestwich's most exact description. This recent accumulation (Plate VII. Fig. II.) strikes the observer at once as consisting essentially of three parts: a shingle-beach of well-rounded flints and fragments of ferruginous sandstones; a mass of Chalk-rubble; and, thirdly, an accumulation of angular flints. The raised beach (Fig. II. 6) rests partly against a former cliff and partly upon a former sea-bed of Chalk, and at its most south-westerly extent it is situated about 12 or 15 feet above the present high-water level. From that elevation it dips gradually in the direction of Sangatte, until it passes out of sight beneath the shingle of the existing shore. The large wellrounded flints which compose it are firmly cemented together in a chalky matrix, and blocks of this conglomerate are to be seen scattered on the beach. Resting upon this shingle-bed is the mass of chalky débris (Fig. II. 4): many of the fragments of chalk are more or less rounded either by gentle water-action or by long-continued exposure to the atmosphere during a period of very gradual accumulation. Here and there in this I noticed collections of small quartz gravel (4′), which seem to me to favour the idea that it is at least partly of subaqueous origin. Somewhat nearer to Sangatte than where the ancient beach disappears, green and brown sands (Fig. II. 5), stratified in beds, one or two feet in thickness, occur below the Chalk-rubble, and with these also I noted the presence of the small quartz gravel. The junction of the sands with the shingle below is concealed by the crumbling away of the loose beds above,

yet their connection with the raised beach is so clearly suggested by their relative position, that I was altogether bewildered when I found, on reference, that D'Archiac' assigned them to the older Tertiary. The third component of the group is, in character, an excellent example of what De la Beche,2 in his description of raised beaches, termed a "head;" in position, however, it is far removed from any cliff or steep elevation whence the angular fragments could have fallen, whilst they also seem too large to be a "rain-wash;" so that, in spite of its appearance, the observer is forced to the conclusion that the materials of which it is composed have been transported from a distance; but, by what agency?

Whilst the appearance of this raised beach and its accompaniments was still fresh in my mind, I chanced to be examining the coast between Wissant and Cap Blanc-nez, when I was much struck by the peculiar appearance of a recent formation, which forms part of a low cliff between the former place and the little hamlet of St. Pol. North of a stream that descends from Sombre-Haute and finds its way through the Sand-dunes to the sea, at about half a mile from Wissant, large blocks of grit, resting upon dark-green sands, and some underlying dark clays, indicate the presence of the Lower Greensand Formation beneath the shore. The higher part of the "between-tide-marks" is here covered by flint-shingle, and at highwater level a bed of shingle, of ancient origin, begins to crop up into sight, from which evidently the flints of the present beach are derived. At first the characters of the old beach are not distinctly seen; but as the observer proceeds in a north-easterly direction, and the Greensand and the Gault form a gradually-rising, low cliff, he will perceive the recent accumulation well exposed, capping the Secondary strata and interposed between them and the Sand-dunes. At the time of my visit it could be clearly traced for 500 paces, and beyond that distance I do not think that it exists; though it may do so, and be concealed by the fall of sand and débris from above. At the point where it ceases to be visible, its base is at least 15 feet over the highest shingle of the shore; so that it rests upon a gradual slope, having a regular inclination of about 1 in 64, in a southwesterly direction. Where it is best exposed, the formation presents the following sequence of characters, and displays the section given in the accompanying figure (Plate VII. Fig. I.).

A bed six feet in thickness of chalk pebbles and rolled flints (Fig. I. 6) rests directly upon the Cretaceous strata; towards the northern end the chalky element rather predominates, the flints being here most thickly packed in the middle of the bed, and more scattered above and below; where, however, it comes down towards the present beach, there is less of the Chalk, and the bed is more exclusively composed of flints. As far as I noticed, the materials are not cemented together; and this, at first sight, led me to think that the accumulation was an equivalent of the Chalk-rubble or

1 D'Archiac Histoire des Progrès de la Geologie, T. 4, p. 200.

2 Report on Geology of Cornwall, etc., p. 432.

debris of the Sangatte example (Fig. II. 4); but, on examination, the well-rolled character of the Chalk-pebbles especially, convinced me that it was a genuine ancient beach. In places the shingle is capped by a bed (Fig. I. 5) six inches thick of greenish sand, greatly resembling the sand occurring above the beach, north of Blanc-nez, and this fact confirmed my impression that the whole was of subaqueous origin. I now regret, however, for a reason given in the sequel, that I did not examine the sand more closely.

Resting upon the patches of greenish sand, or where this is absent directly upon the shingle, is a stratum so largely composed of vegetable remains as to appear to be a layer of bog-earth. This bed (Fig. I. 3), a foot in thickness, throws out much water, which strongly marks the beds below with ferruginous stains; it would seem, however, to contain a considerable proportion of fine greenishgrey sand. Its dark colour renders this deposit a conspicuous object in the low cliff, contrasting as it does so strongly with the lightercoloured beds above and below. Brown sand rests upon the last stratum, and is apparently the same as that of the dunes, but it is separated from the latter, in places where the cliff is sufficiently preserved to show the complete sequence, by a second but much thinner layer of vegetable débris (Fig. I. 2 and 1). Such is the series of deposits that here intervene between the older formations and the Sand-dunes.

On a subsequent visit to the same locality, whilst availing myself of low-water to search for the nethermost beds of the Lower Greensand exposed on this coast, I came upon a most instructive example of an ancient and partially submerged forest. Black patches (Fig. I. 7), which I mistook from a distance for secondary rocks, stood up out of the sand of the shore at low-water level, about 200 yards seaward of the raised beach. On examination, I found them to consist of a peaty formation embedding numerous stumps of trees of various sizes, still standing upright and with their roots running down into the mass below. I traced these trees for a considerable distance along the shore opposite to the raised beach, but time did not allow me to examine the stratum as closely as I wished to do. I noted, however, that the black peaty bed, in the lowest part that I could find exposed, contained numerous white Chalk pebbles scattered through it; and I was further successful in obtaining from amongst the roots of a tree a single bone, the larger portion of the metatarsal of a ruminant, which had every appearance, from its dark colour and great weight (apparently due to an infiltration of iron), of being coeval with the forest. As, however, it contained all or nearly all its animal matter, and I found the colour to be superficial, and as I am, moreover, inexperienced in these recent reliquiæ, and there was every possibility of its being a modern intrusion into the ancient deposit, I was glad on my return to have an opinion upon its antiquity. Mr. Wm. Davies, of the British Museum, who kindly compared it for me with corresponding bones in the national collection, tells me that, in his opinion, it may be assigned to the Aurochs (Bison priscus ?), which puts its contemporaneity with the