Though one of its names is “culture,” it has grown sporadically and unevenly, with little evidence of the cultivation that is implied and required. Parts have been expanded to extraordinary proportions while others equally essential have been retarded in their growth. A more intelligent handling of this environment factor seems to be possible, and the present mania for “organization” may become tempered with an awakening consciousness of organic requirements where organism and environment are involved. Once we grasp the idea that “culture” results from man’s effort to improve his living, by putting into his environment something that was not there before—then, surely, this history of a billion years of living, and as many “ways of life,” should teach us something we ought to know as we go into an all-out endeavor to teach a whole world how to obtain a one-and-only way. We may stand at the beginning of an era for which an appropriate name has not yet been suggested. Civilization, on the other hand, may provide only a minor epoch to be added in some remote time to the story of fossils. SUPPLEMENTARY READING The literature pertaining to fossils is widely scattered and usually too technical for the layman. It is better to use the resources of the nearest library than to feel that a specified list of books is necessary. Any textbook on geology, zoology, or botany will provide helpful information. Most books of this type will be found interesting and readable if used to solve definite problems suggested by the student’s immediate curiosity. Very few can be read from beginning to end without a great deal of effort and discouragement. The following have been prominent among the books consulted by the author: _Textbook of Geology_; by Pirsson and Schuchert. This work has undergone several revisions and currently appears in two volumes: _Physical Geology_ by Longwell, Knopf, and Flint; _Historical Geology_ by C. O. Dunbar. Published by John Wiley & Sons. (Historical geology covers the entire range of prehistoric life—plant, invertebrate, and vertebrate.) _Historical Geology_ (The Geologic History of North America); by Russell C. Hussey. Published by McGraw-Hill. Concise, interesting, and informative. _Geology and Natural Resources of Colorado_; by R. D. George. Published by the University of Colorado. Contains an excellent summary of the historical geology and sedimentary formations of Colorado. _Vertebrate Paleontology_; by Alfred Sherwood Romer. Published by the University of Chicago Press. This is one of the most comprehensive and up-to-date treatments of the subject for students desiring to go beyond the elementary stage. _A History of Land Mammals in the Western Hemisphere_; by William Berryman Scott. Published by The Macmillan Company. This well-known account of living and extinct mammals is one of the favorites among students.