under such conditions of comparative rest, as to allow the development of a glacial fauna. Close to my own residence on the Clyde each low ebb exposes numerous examples of the Pecten Islandicus and of those very large Balani, which are confined to arctic seas. These beds of shells, which are all of existing species, but of species which have retired from our now more genial temperature to a northern habitat, were first described by my friend Mr. Smith of Jordanhill, and his observations and conclusions have since been abundantly confirmed. We have no knowledge how this period was brought to a close. But there seems to be evidence that it had come to an end, and that for a long time before the last elevation of the land, and before man had appeared in Scotland. This seems to be a legitimate deduction from the fact that the canoes in the elevated Clyde beds are formed of oak of large dimensions and of great age. Forests which afforded such timber must have flourished in a climate not much more rigorous than that which exists at present. Here again, then the earliest footprints of our race are traced up to a point, preceding indeed some important physical changes, but clearly subsequent to the establishment of all the main conditions which now affect the distribution of animal and vegetable life.

As regards the extinction of some animals, I have spoken as if the contemporaneousness of man with them whilst yet living ought not to be absolutely assumed merely from the fact that his implements are associated with their bones. But on this point new evidence is being rapidly collected and brought together. Mons. Lartet, a distinguished French naturalist, has found what he considers to be a distinct evidence of the mark of human weapons on various parts of the skeletons of the extinct mammalia of the drift. These marks have been detected on the skull of the Megaceros Hibernicus, or great Irish elk-an animal which stood some ten feet high-on the bones of the Rhinoceros tichorinus, and on those of various species of the ox and deer, which are now either extinct or confined to the last remnants of a declining race. The marks are of various kinds-some of them peculiar-indicating a sort of sawing with some instrument not of the smoothest edge. M. Lartet has ascertained that these blows and cuttings could not be made except on fresh bones-that is to say, on bones undried and retaining their animal cartilage. Farther he has suceeeded in producing on the bones of existing animals precisely

the same peculiar forms of incision by using one of the old flint implements found in the same beds of gravel, whilst he has equally found that similar marks are incapable of being produced by implements of metallic edge. His conclusion is thus stated by himself:-"If, therefore, the presence of worked flints in the diluvial banks of the Somme, lone since brought to light by M. Boucher de Perthes, and more recently confirmed by the rigorous verifications of several of your learned fellow-countrymen, have established the certainty of the existence of man at the time when those erratic deposits were formed, the traces of an intentional operation on the bones of the rhinoceros, the aurochs, the megaceros, the cervus sommensis, &c. &c., supply equally the inductive demonstration of the contemporaneousness of those species with the human race."

The great number of flint implements which have been found in the French beds-said to amount to upwards of a thousand in a few years—when compared with their great rarity elsewhere, is not perhaps so curious as at first sight it may appear to be. Flint implements can only be made where flints are accessible; and it is well known that the flints of particular beds, or strata of the chalk, are more easily fashioned than others. It is therefore probable that some such favourable locality had existed in the chalk of that part of France, and that what may be called a manufactory of them had been established there. It is remarkable that some of the implements are only half finished, whilst all of them exhibit such sharp edges and angles as are sufficient to prove that they have not been transported far from the spot where they were made, nor subjected to long wear from use.

On the whole, then, it is not to be doubted that the discovery of human implements under repeated beds of aqueous drift and and sediment, so high above the levels of exising rivers, or of the existing sea, is a fact of very great significance and importance. In its bearing on geology, it is principally interesting as proving at how recent a period portions at least of the earth have been subject to powerful and rapid diluvial action. In its bearing on human chronology, everything depends on the degree of suddenness and rapidity with which water may have been brought to act upon the former surface. But here anything like data for positive computation entirely fails us. We have no knowledge, in historic times, of any aqueous operation on so grand a scale. Making

however, every deduction which can be made, we must be prepared to find that the facts thus brought to light in the valley of the Somme will be held to furnish important collateral evidence in support of the reasoning founded on other sciences, such as philology and ethnology, which has long demanded, for the development of our race, a number of years far exceeding that which is allowed by the chronology previously received. It is the beautiful expression of Sir Thomas Browne, which I find quoted by Dr. Mantell in a former paper on this subject, that "Time conferreth a dignity upon the most trifling thing that resisteth his power: and it is impossible to look at these rude implements-perhaps the earliest efforts of our race, in the simplest arts of life—without being impressed with the high interest of the questions with which they seem to be inseparably connected.

ARTICLE XIV.-Considerations relating to the Quebec Group, and the Upper Copper-bearing rocks of Lake Superior. By SIR W. E. LOGAN, F.R.S., Director of the Geological Survey of Canada.

(Read before the Nat. Hist. Society.)

In a communication addressed by me to Mr. Barrande on the fauna of the Quebec group of rocks, (Canadian Naturalist and Geologist vol. v. p. 472), after showing that the organic remains discovered last year at Point Lévi placed the group about the horizon of the Calciferous formation, I stated that the apparent conformable superposition of the group on the Hudson River formation was probably due to an overturn anticlinal fold or overlap.

Horizontal and vertical scale, 1 inch to 1 mile.

The character of this overlap is exhibited in the accompanying wood cut (fig 1) of a vertical section in the neighbourhood of Quebec, extending from the Montmorency side of the St. Lawrence across the north channel and the upper end of the Island of

Orleans. The road from Beauport to the Montmorency runs over a floor of Trenton limestone, which has a very small dip towards the St. Lawrence; farther back from the river the rock has a gentle dip in an opposite direction giving evidence of a very flat anticlinal form, which could scarcely be detected without the aid of the general distribution of the formations in the neighbourhood. On the south side of the road there occurs a dislocation which can be traced the whole way from Beauport church to Montmorency falls, where the effect it produces is easily discernible. Here the channel of the Montmorency is cut down through the black beds of the Trenton formation to the Laurentian gneiss on which they rest, and the water at and below the bridge flows down and across the gneiss, and leaps at one bound to the foot of the precipice, which immediately behind the water is composed of this rock. At the summit the Trenton beds are seen on each side; on the right bank they have a thickness of about fifty feet, and are marked by the occurrence of Leptana sericea (Sowerby), Strophomena alternata (Conard), Orthis testudinaria (Dalman) Lingula crassa (Hall), Conularia Trentonensis (Hall), Calymene Blumenbachii (Brongniart), and Trinucleus concentricus (Eaton). The dip of these beds is down the stream at a very small angle; but at the foot of the precipice and immediately in contact with the gneiss, about the same thickness of black limestone is tilted up to an angle of fifty-seven degrees; it is followed by about an equal amount of black bituminous shale with the same slope. In this attitude these rocks climb up the face of the precipice presenting their edges to the chasm on each side; they are succeeded by about eight feet of hard grey sandstone weathering brown in beds of from ten to eighteen inches, interstratified with black shale; on this repose gray arenaceo-argillaceous shales composing the sides of the chasm out to the waters of the St. Lawrence, the distance being about a quarter of a mile, and the dip which is towards the St. Lawrence by degrees diminishing to about thirtyfive degrees.

These tilted beds are fossiliferous, the species contained in the limestones being Stenopora petropolitana (Pander), Ptilodictya acuta, (Hall), Strophomena alternata, Leptona sericea, Orthis testudinaria, Camerella nucleus (Hall), Lingula allied to L. obtusa, Descina crassa (Hall), Bellerophon bilobatus (Sowerby), Conularia Trentonensis, an undetermined Orthoceras, Cyrtoceras constrictum (Hall), Calymene Blumenbachii, Cheirurus pleurexan

themus (Green), Trinucleus concentricus, Asaphus platycephalus (Stokes); those contained in the black shales are Graptolithus bicornis (Hall), G. pristis (Hessinger). There is thus no doubt whatever that the limestones are of the Trenton and the shales of the Utica formation.

On the opposite side of the north channel at the upper end of

the Island of

ERRATUM.

Page 201, line 12, for "They dip S.W.," read "They dip S.E."

tion. They dip S. W. <50°, and there rests upon them (the contact being visible) a series of magnesian shales and conglomerates dipping in the same direction and at the same angle. These magnesian strata are of the same character as those at Point Levis, and belong to the Quebec group. They thus overlap the black shales which are probably overturned as represented in the diagram (fig. 1).

c, Huronian slate conglomerate and jaspar conglomerate.
H, Level of Lake Huron.

S, Level of the Sea.

Horizontal and vertical scale, 1 inch to 1 mile.

In his explorations of last year on Lakes Superior and Huron Mr. Murray ascertained that the lowest rock in that neighbourhood well characterised by its fossils belongs to the Birdseye and Black River group, and that it rests conformably upon the sandstones of Sault Ste. Marie. These sandstones and their equivalents, consisting of red and yellowish-white beds, are traceable on the south side of Lake Superior from Marquette to the River St. Marie and compose Sugar Island and probably the north part of Neebish Island; they extend to the north part of St. Joseph Island, and are met with on the Island of Campment d'Ours. In one of the white beds near Marquette, Mr. Murray obtained a Pleurotomaria resembling P. Laurentina of the Calciferous formation and observed the occurrence in the same bed of a species of Scolithus. The mass