We are in fact face to face with most formidable problems, involving alike our past and future; problems it is hopeless to attempt to solve by human means or by the help of human intelligence alone, yet with which science can and ought to grapple, for they elevate the soul and strengthen the reasoning faculties. Whatever may be their final result, such studies are of enthralling interest. “Man,” said a learned member of the French Institute, “will ever be for man the grandest of all mysteries, the most absorbing of all objects of contemplation.”1 Let us work our way back through past centuries and study our remote ancestors on their first arrival upon earth; let us watch their early struggles for existence! We will deal with facts alone; we will accept no theories, and we must, alas, often fail to come to any conclusion, for the present state of prehistoric knowledge rarely admits of certainty. We must ever be ready to modify theories by the study of facts, and never forget that, in a science so little advanced, theories must of necessity be provisional and variable. Truly strange is the starting-point of prehistoric science. It is with the aid of a few scarcely even rough-hewn flints, a few bones that it is difficult to classify, and a few rude stone monuments that we have to build up, it must be for our readers to say with what success, a past long prior to any written history, which has left no trace in the memory of man, and during which our globe would appeal to have been subject to conditions wholly unlike those of the present day. The stones which will first claim our attention, some of them very skilfully cut and carefully polished, have been known for centuries. According to Suetonius, the Emperor Augustus possessed in his palace on the Palatine Hill a considerable collection of hatchets of different kinds of rock, nearly all of them found in the island of Capri, and which were to their royal owner the weapons of the heroes of mythology. Pliny tells of a thunder-bolt having fallen into a lake, in which eighty-nine of these wonderful stones were soon afterwards found.2 Prudentius represents ancient German warriors as wearing gleaming _ceraunia_ on their helmets; in other countries similar stones ornamented the statues of the gods, and formed rays about their heads.3 A subject so calculated to fire the imagination has of course not been neglected by the poets. Claudian’s verses are well known: Pyrenæisque sub antris Ignea flumineæ legere ceraunia nymphæ. Marbodius, Bishop of Rennes, in the eleventh century, sang of the thunder-stones in some Latin verses which have come down to us, and an old poet of the sixteenth century in his turn exclaimed, on seeing the strange bones around him Le roc de Tarascon hébergea quelquefois Les géants qui couroyent les montagnes de Foix, Dont tant d’os successifs rendent le témoignage.