The indefatigable labors of Prestwich, in the basin of the Somme and among the gravel-beds of Picardy, first called the attention of geologists to the fact that works of men's hands were also found in undisturbed alluvial deposits of high antiquity, and he had the honor of bringing to light proofs of the existence of man in Europe in more remote times than had been previously admitted, and of demonstrating the stone age of France. Goss, Hebert, and Lartet followed in the same track, and added many valuable facts, and a host of other laborers in the same field have since appeared. So extensive have been the discoveries of the works of man buried with the bones of the _Elephas primigenius_ and of cavern-bears and extinct hyenas, that we are forced to recognize the fact of the coexistence of man with those ancient animals, for the occurrence of deposits containing the bones of the two cannot any longer be regarded as doubtful; and certainly stone tools fashioned by man have been found so widely spread in the ancient alluviums and deposits of the post-Pliocene age, as to remove all doubt of the fact, and to destroy the objection that they might be local accidents of an equivocal character. More recently,--namely, within four or five years,--the discovery of the habitations of lost races of men on the borders of the Swiss lakes, and of remains of various articles which those people once used,--tools, weapons, ornaments, bones of animals they fed upon, seeds of plants they cultivated and consumed,--has given a new impetus to these researches into the antiquity of the human race. Borings into the alluvial deposits of the Nile have proved the existence of man in that valley more than thirty thousand years ago, as estimated by the known rate of deposit of the alluvium of the Nile. Considerations as to the origin and spread of languages also seem to require a much greater antiquity for the human race than has been popularly allowed; and geologists have always claimed myriads of years as required for the sedimentary formations of the globe. Sir Charles Lyell, ever an active collector of geological facts, and an excellent writer on the science of Geology, has engaged with his usual zeal in verifying the researches of the French, Swiss, and German geologists, and has written a very readable book on these new revelations concerning the ancient history of the human race. It is the best English presentation of the subject, and is written in a style that every one can read and understand.