A great catastrophe, the tradition of which is preserved in the memory of all nations, marked in Europe the end of the quaternary epoch. It is not easy to assign the exact causes for this great event in the earth's history; but whatever may be the explanation given, it is certain that a cataclysm, caused by the violent flowing of rushing water, took place during the quaternary geological epoch; for the traces of it are everywhere visible. These traces consist of a reddish clayey deposit, mixed with sand and pebbles. This deposit is called in some countries _red diluvium_, and in others _grey diluvium_. In the valley of the Rhone and the Rhine it is covered with a layer of loamy deposit, which is known to geologists by the name of _loess_ or _lehm_, and as to the origin of which they are not all agreed. Sir Charles Lyell is of opinion that this mud was produced by the crushing of the rocks by early Alpine glaciers, and that it was afterwards carried down by the streams of water which descended from these mountains. This mud covers a great portion of Belgium, where it is from 10 to 30 feet in thickness, and supplies with material a large number of brickfields. This deposit, that is the _diluvial beds_, constitutes nearly the most recent of all those which form the earth's crust; in many European countries, it is, in fact the ground trodden under the feet of the present population. The inundation to which the _diluvium_ is referred closes the series of the quaternary ages. After this era, the present geological period commences, which is characterised by the almost entire permanency of the vertical outline of the earth, and by the formation of peat-bogs. The earliest documents afforded us by history are very far from going back to the starting-point of this period. The history of the ages which we call historical is very far from having attained to the beginning of the present geological epoch. In order to continue our account of the progressive development of primitive man, we must now turn our attention to the _Polished-stone Epoch_, or the _Epoch of Tamed Animals_, which precedes the Metal Age. As the facts which we shall have to review are very numerous, we will, in the first place, consider this epoch as it affects those parts of our continent which form the present France and Belgium; next, with reference to Denmark and Switzerland, in which countries we shall have to point out certain manners and customs of man of an altogether special character. We shall consider in turn:-- 1st. The habitation of man during the polished-stone epoch. 2nd. His system of food. 3rd. His arts and manufactures. 4th. The weapons manufactured by him, and their use in war. 5th. His attainments in agriculture, fishing, and navigation. 6th. His funeral ceremonies. 7th. Lastly, the characteristics of mankind during this epoch.