CHAPTER XI. Collecting Dinosaurs. How and Where they are Found. The First Discovery of Dinosaurs in the West. The Bone-Cabin Quarry. Fossil Hunting by Boat in Canada. 116 PREFACE. This volume is in large part a reprint of various popular descriptions and notices in the American Museum Journal and elsewhere by Professor Henry Fairfield Osborn, Mr. Barnum Brown, and the writer. There has been a considerable demand for these articles which are now mostly out of print. In reprinting it seemed best to combine and supplement them so as to make a consecutive and intelligible account of the Dinosaur collections in the Museum. The original notices are quoted verbatim; for the remainder of the text the present writer is responsible. Professor S.W. Williston of Chicago University has kindly contributed a chapter--all too brief--describing the first discoveries of dinosaurs in the Western formations that have since yielded so large a harvest. The photographs of American Museum specimens are by Mr. A.E. Anderson; the field photographs by various Museum expeditions; the restorations by Mr. Charles R. Knight. Most of these illustrations have been published elsewhere by Professor Osborn, Mr. Brown and others. The diagrams, figs. 1-9, 24, 25, 37 and 40, are my own. W. D. M. CHAPTER I. THE AGE OF REPTILES. ITS ANTIQUITY, DURATION AND SIGNIFICANCE IN GEOLOGIC HISTORY. Palaeontology deals with the History of Life. Its time is measured in geologic epochs and periods, in millions of years instead of centuries. Man, by this measure, is but a creature of yesterday--his "forty centuries of civilization"[1] but a passing episode. It is by no means easy for us to adjust our perspective to the immensely long spaces of time involved in geological evolution. We are apt to think of all these extinct animals merely as prehistoric--to imagine them all living at the same time and contending with our cave-dwelling ancestors for the mastery of the earth. In order to understand the place of the Dinosaurs in world-history, we must first get some idea of the length of geologic periods and the immense space of time separating one extinct fauna from another.