Hugo Obermaier and of Déchelette in the Lower Palæolithic, and of Henri Breuil in the Upper Palæolithic. Through the courtesy of Doctor Obermaier I had the privilege of watching the exploration of the wonderful grotto of Castillo, in northern Spain, which affords a unique and almost complete sequence of the industries of the entire Old Stone Age. This visit and that to the cavern of Altamira, with its wonderful frescoed ceiling, were in themselves a liberal education in the prehistory of man. With the Abbé Breuil I visited all the old camping stations of Upper Palæolithic times in Dordogne and noted with wonder and admiration his detection of all the fine gradations of invention which separate the flint-makers of that period. With Professor Cartailhac I enjoyed a broad survey of the Lower and Upper Palæolithic stations and caverns of the Pyrenees region and took note of his learned and spirited comments. Here also we had the privilege of being with the party who entered for the first time the cavern of Tuc d'Audoubert, with the Comte de Bégouen and his sons.

In the American Museum I have been greatly aided by Mr. Nels C. Nelson, who has reviewed all the archæological notes and greatly assisted me in the classification of the flint and bone implements which is adopted in this volume.

In the study of the divisions, duration, and fluctuations of climate during the Old Stone Age I have been assisted chiefly by Doctor Chester A. Reeds, a geologist of the American Museum, who devoted two months to bringing together in a comprehensive and intelligible form the results of the great researches of Albrecht Penck and Eduard Brückner embraced in the three-volume work, Die Alpen im Eiszeitalter. The temperatures and snow-levels of the Glacial Epoch, which is contemporaneous with the Old Stone Age, together with the successive phases of mammalian life which they conditioned, afford the firm basis of our chronology; that is, we must reckon the grand divisions of past time in terms of Glacial and Interglacial Stages; the subdivisions are recorded in terms of the human invention and progress of the flint industry. I have also had frequent recourse to The Great Ice Age and the more recent Antiquity of Man in Europe of James Geikie, the founder of the modern theory of the multiple Ice Age in Europe.

It is a unique pleasure to express my indebtedness to the Upper Palæolithic artists of the now extinct Crô-Magnon race, from whose work I have sought to portray so far as possible the mammalian and human life of the Old Stone Age. While we owe the discovery and early interpretation of this art to a generation of archæologists, it has remained for the Abbé Breuil not only to reproduce the art with remarkable fidelity but to firmly establish a chronology of the stages of art development. These results are brilliantly set forth in a superb series of volumes published by the Institut de Paléontologie humaine on the foundation of the Prince of Monaco; in fact, the memoirs on the art and industry of Grimaldi, Font-de-Gaume, Altamira, La Pasiega, and the Cantabrian caves of Spain (Les Cavernes de la Région Cantabrique), representing the combined labors of Capitan, Cartailhac, Verneau, Boule, Obermaier, and Breuil, mark a new epoch in the prehistory of man in Europe. There never has been a more fortunate union of genius, opportunity, and princely support.

In the collection of materials and illustrations from the vast number of original papers and memoirs consulted in the preparation of this volume, as well as in the verification of the text and proofs, I have been constantly aided by one of my research assistants, Miss Christina D. Matthew, who has greatly facilitated the work. I am indebted also to Miss Mabel R. Percy for the preparation and final revision of the manuscript. From the bibliography prepared by Miss Jannette M. Lucas, the reader may find the original authority for every statement which does not rest on my own observation or reflection.

Interest in human evolution centres chiefly in the skull and in the brain. The slope of the forehead and the other angles, which are so important in forming an estimate of the brain capacity, may be directly compared throughout this volume, because the profile or side view of every skull figured is placed in exactly the same relative position, namely, on the lines established by the anatomists of the Frankfort Convention to conform to the natural pose of the head on the living body.

In anatomy I have especially profited by the co-operation of my former student and present university colleague Professor J. Howard McGregor, of Columbia, who has shown great anatomical as well as artistic skill in the restoration of the heads of the four races of Trinil, Piltdown, Neanderthal, and Crô-Magnon. The new reconstruction of the Piltdown head is with the aid of casts sent to me by my friend Doctor A. Smith Woodward, of the British Museum of Natural History. The problem of reconstruction of the Piltdown skull has, through the differences of interpretation by Smith Woodward, Elliot Smith, and Arthur Keith, become one of the causes célèbres of anthropology. On the placing of the fragments of the skull and jaws, which have few points of contact, depends the all-important question of the size of the brain and the character of the profile of the face and jaws. In Professor McGregor's reconstruction different methods have been used from those employed by the British anatomists, and advantage has been taken of an observation of Mr. A. E. Anderson that the single canine tooth belongs in the upper and not in the lower jaw. In these models, and in all the restorations of men by Charles R. Knight under my direction, the controlling principle has been to make the restoration as human as the anatomical evidence will admit. This principle is based upon the theory for which I believe very strong grounds may be adduced, that all these races represent stages of advancing and progressive development; it has seemed to me, therefore, that in our restorations we should indicate as much alertness, intelligence, and upward tendency as possible. Such progressive expression may, in fact, be observed in the faces of the higher anthropoid apes, such as the chimpanzees and orangs, when in process of education. No doubt, our ancestors of the early Stone Age were brutal in many respects, but the representations which have been made chiefly by French and German artists of men with strong gorilla or chimpanzee characteristics are, I believe, unwarranted by the anatomical remains and are contrary to the conception which we must form of beings in the scale of rapidly ascending intelligence.

Henry Fairfield Osborn.

American Museum of Natural History
June 21, 1915.

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