6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL.83 



Tlic length of time represented by such Hfe 011 the earth as has 

 left distinguishable traces, or from the Archeozoic era to the present, 

 is enormous, comprising perhaps nK)re than one hundred million 

 years, though all estimates of geological time in years are notoriously 

 uncertain. The greater part of this time, however, has only a secon- 

 dary importance to man, the period of direct concern to him beginning 

 only during the Tertiary period of the Cenozoic era. During the early 

 part of this, in the Eocene or "dawn" iKTiod, there appear in 

 America and elsewhere the earliest known mcnibers'of the order of 

 primates, the parent-order of Man. In the Miocene there are already 

 numerous monkeys and later even some anthropoid apes. The Plio- 

 cene is the age of the higher apes and from among these, during 

 the latter part of this period, there begin, in all probability, further 

 differentiations that lead to forms which could only be classified as 

 human precursors. Then finally comes the Ice Age, and from the 

 earlier ])arts of this, if not even liefore, there commence to lie found 

 indications of beings still higher in the scale, beings that have begun 

 to shape tools of stone and other materials ; and these teings, though 

 still very primitive in every way, can no more be conceived as pre- 

 cursors — they are evidently rejiresentatives of the earliest men. Such, 

 in brief, is the jirevalent view of the a])i>earance of man on the earth. 

 From that point on, the evidence relating to him grows steadily in 

 mass. It shows his slowly progressive cultural and physical advance 

 with no geneial interru])tion until he connects with man of proto- 

 history and then history. 



The peculiarly important relation of the Ice Age to man's existence 

 and differentiation makes it highly desirable that we have the fullest 

 possible knowledge of this period. For such knowledge the student 

 of man must look to geology and paleontolog}', and these, regrettably, 

 are not yet in a position to furnish all that is needed, owing to the 

 great complexities of the subject. 



There was a time in the earlier part of this century when, due 

 especially to the discerning work of Penck and Briickner,' a good 

 general understanding of the Ice Age seemed to have been reached. 

 The era was represented as having consisted of four glacial invasions, 

 called resjiectively, after the Ali)ine localities where best represented, 



' Pcnck, A., and Briickner, Iv, Die .'Mpcn im Eiszcitaltcr, 3 vols., Leipzig, 

 1901-1909; with nunieruus smaller, both earlier and later, contributions by these 

 authors. 



