level and contour. England was broken off from France, the British islands formed, and the rivers reduced to their present size and courses.

Sir C. Lyell says:-"The naturalist would have been entitled to assume the former union, within the postpliocene period, of all the British isles with each other, and with the Continent, even if there had been no geological facts in favour of such a position."*

The recent examination of the bed of the English Channel, for the purposes of a submarine tunnel, confirms the conclusion that its disruption is only of recent geological date, that it is a denuded hollow in the line of ancient rivers, broken into by oscillation, and pared down by the inroad of the sea in postglacial times.t

(4.) I will briefly refer to the cave evidence. England and Wales, like most European countries, contain caves that have been occupied by man from the earliest times to the present. They inclose not only relics of all ages since they were the dwellings or resorts of the people first encountered by the Romans, but of a still earlier race whose implements are found sealed up in stalagmite, with bones of extinct mammals of the same epoch as the valley and terrace gravels. All such caves are within one hundred and fifty feet of running water, or of the sea, the majority of them within seventy or eighty feet. The lowest fossil contents ascertained, correspond with the lowest fossiliferous gravels. I will just refer to a few of these. Kent's Cavern, at Torquay, offers us in its lowest bed a typical instance of the occurrence of man's works contemporaneously with the mammoth. This locality is familiarized to us all by the popular demonstrations of Mr. Pengelly. The stratum in question was accumulated or drifted when the entrance to the cave was from seventy to one hundred feet lower than at present relatively to the sea-level. After an elevation had first taken place, a second depression occurred, bringing the cave floor level with the sea beach; since that, gradual changes only have followed, from causes now in operation, resulting in the present contour of the country. Uuquestionably this indicates vast lapses of time; but the two principal factorsthe raising and submersion-require the intervention of causes

Age of Man, p. 277.

I much regret that, at the time of writing, I had not before me Professor Geikie's able work on the "Great Ice Age." In discussing it I should have claimed him as a witness for catastrophe at this epoch, on the ground of that which he terms-" those mysterious forces by which the solid crust of the globe is elevated and depressed" (p. 509).

not now in operation in the district. We know not how suddenly they may have arisen and fulfilled their course. A space of two thousand years is adequate to account for all the phenomena, if we take this into account, whilst, on the other hand, no allowance of time whatever is adequate to account for it on the other supposition, i.e. as effected by causes now progressing

here.

Brixham Cave is another in which works of man are in the lowest stratum. It has been channelled by a strong stream of running water flowing through the crevices of the rock from the table-land above; the waters were gathered in the cave, and rushing out by a stream to the sea 60 feet higher than the present base of the surrounding valleys. In Brixham Cave the remains of the mammoth,-gnawed bones,-occur in the lowest bed. The implements are worked flints of the simplest shape, triangular and lance-shaped, with cutting edges. The bones were some of them carried in by water with pebbles and mud, others by beasts of prey inhabiting the cave.

"Water charged with silt probably found its way into the cave by the lower or north entrance, and deposited the cave earth, in which occurs so great an accumulation of bones, including, in addition to the above-named animals, those of the various deer, bear, fox, rhinoceros, hare, and lemming. Looking at all the circumstances of the case, I consider it most probable that at that second period the cave was at times dry, and at other times flooded, not by streams flowing in from higher ground, but by flood waters from streams at a level lower than that of the cave; that during the former interval the cave continued to be frequented by carnivores, who brought in their prey to devour; and that by each successive inundation successive collections of bones were covered up and imbedded in the sediment with which the flood waters were charged."* In Brixham Cave there occurred thirty-six specimens of flint, fifteen of which had been artificially worked. Mr. Prestwich suggests that the flints were lost or left behind by man during occasional visits to the cave, either for the sake of temporary refuge, or in following prey which may have sought shelter there.

He further considers that we can only account for the phenomena of Brixham Cave on the suppositions:

1. Of greater rainfalls.

2. Of an intensely cold climate.

* Prestwich, p. 558.

3. Spring floods of great power, such as now occur in Arctic regions.

4. Sea action.

5. A slow movement of elevation.

Mr. Boyd Dawkins, in his ample and able researches into the subject, embodied in his most interesting book, referring to the Victoria Cave at Settle, estimates that the two feet of débris accumulated at its mouth since the ancient British period, supplies a chronometer, and indicates the lapse of 1,200 years. He applies this to the six feet between this and the floor of the men of the polished stone period (neolithic), and thus makes the latter 3,600 years ago; and then to the still earlier (mammoth) age, which brings the occupation of the cave by man to about 5,000 years ago. But he admits that in ancient times the frosts may have been more intense than they are now, and therefore that the rate of weathering may have been faster.* Thus the calculation is invalidated, and one-half the number of years has equal claims on our belief,-or superior, if favoured with other considerations.

There are a sufficient number of good instances of the occurrence of bones with paleolithic implements only, to warrant the conclusion that the early cave period is synchronous with that of the gravels. The cave was the resort of the first hunters.

The most remarkable and complete of the Belgian caves are those on the Meuse and its tributaries, described in the able work of M. Dupont, Director of the Natural History Museum at Brussels. No less than forty-three caverns which open in the limestone cliffs of the Meuse or its tributaries have been carefully explored; of these, twenty-five have furnished remains of man's work associated with extinct mammals. The caves open at heights varying in different parts of the valley from 12 to 60 yards from its level. They all have a floor of ancient mud, the result of periodical inundations of the river. Some of the bones were thus washed in, but the greater part were accumulated during occupation by living men and animals. We select one of the twenty-five caves,-that of Magrite, near Pont-à-Lesse. Dry, large, open, light, it has been often chosen as a convenient abode. Its floor is covered with rolled pebbles and 2 yards of river mud, including four distinct successive surfaces, and each layer containing bones. These remains vary

*Prestwich, p. 115.

+ L'Homme pendant les Ages de Pierre dans les Environs de Dinant-surMeuse et Bruxelles. 1872.

from stage to stage. The lowest bed contains worked flints of rude triangular form, and some other used stones. In this ancient mud, and with these implements of man, washed by water, but not transported, are found the bones of

and many others. I will not enumerate further, but refer you to M. Dupont's book. The upper layers contain fewer of extinct mammals and more of the bones of the reindeer and horses. The flint tools, too, exhibit some slight advance in art. In the third bed was found a carved reindeer bone, with cut ornamentation. Some of the bones in the earliest deposits display traces of designed fracture and cutting. In their selection and treatment they show the action of man's mind. In many cases the mode of introduction of mammoth bones and flints is not clear; they may have been introduced by crevices, or surface floods, but in others the evidence is that of entry by the open mouth of the cave. In both, the floor has been covered by mud of inundation, occupied by man and beast of prey, abandoned and sealed over by stalagmite, then after an interval occupied again; and thus it has gone on until recent times. In one case there are six beds of ossiferous mud, and five layers of stalagmite. The openings of the caves in Belgium once flooded by the stream of the valley, are now 200 feet above the latter, in solid limestone. It has therefore been inferred that 200 feet have been scooped out of the valley by causes now in operation since the inhabitancy of the cave. But there is no appreciable lowering of the valley going on now, and therefore this reasoning is obviously illusory. There is no such cause in operation.

This is precisely analogous to the alleged scooping out of the wide valley of the Somme. The one is as impossible as the other, and if geologists have to bring in other and more powerful causes for the one set of effects, they must do the same for the other also. The only interpretation of the Belgian caves, in regard to their mud deposits, is that which assigns the material to the drifting and sorting powers of water

intermittent between periods of occupation during which they were dry. In other words, they were on the borders of a river, subject to inundation, and within the limits of the inundation. The caves of the Dordogne and of Bruniquel, in France, do not present the action of floods, but accretion of soil by inhabitation without disturbance. Undoubtedly they show that wild animals now extinct haunted these caves and that man hunted them, and used them for food, and also the flesh of reindeer in a district where the latter do not now exist, besides that of some creatures still living in the district.

As far then as geological evidence of antiquity goes, it is merely a question as to what changes have taken place in the valleys since the accumulation of the soil forming the floors, what was the time necessary for the formation of the stalagmite which in some cases overlies them, and of the calcareous breccia into which they have been converted. These are dependent upon such variable conditions that it seems. utterly hopeless to attempt to assign positive dates. Here, again, we have to quote from Mr. Prestwich the cautious remark:-"Some doubt must always attach to the determination of the relative antiquity of the cave remains, owing to the several possible causes of disturbance, whether by physical operations which re-arranged the contents of the cave, or by the agency of animals or of man producing local displacements." "'*

And with regard to the stalagmite on which so much stress has been laid as proving extreme antiquity, various observers,Mr. Farrar, at the Victoria Cave; Professor Phillips in the Ingleborough Caves; and Mr. Dawkins,-may be said to have established the average rate, at a quarter of an inch per annum ; (i.e.) 20 feet of stalagmite may be formed in 1,000 years; and, says the last named,-" It may fairly be concluded, that the layers of stalagmite cannot be used as an argument in support of the remote age of the strata below."+

The mammoth or palæolithic age, and the reindeer or neolithic age, cannot always be sharply separated though usually betraying change of level between them. Perhaps in America they cannot be separated at all. Some of the French and Belgian caves of the first stage show that the rudest implement contained was still used among the later people. But on the whole the distinction is real and well-founded, and indicates true succession. Palæolithic man may have been altogether a transitory visitor in these parts. His cave abodes may have been mere

* Report on Brixham Cave, p. 560.

+ Ib., p. 40.