TRANSCRIBER’S NOTE Italic text is denoted by _underscores_. Footnote anchors are denoted by [number], and the footnotes have been placed at the end of the book. The tables in this book are best viewed using a monospace font. Some minor changes to the text are noted at the end of the book. THE EVOLUTION OF CLIMATE THE EVOLUTION OF CLIMATE BY C. E. P. BROOKS, M.Sc., F.R.A.I., F.R.Met.Soc. WITH A PREFACE BY G. C. SIMPSON, D.Sc., F.R.S., DIRECTOR OF THE METEOROLOGICAL OFFICE LONDON: BENN BROTHERS, LIMITED 8 BOUVERIE STREET, E.C.4 1922 PREFACE Geologists very early in the history of their science, in fact as soon as fossils began to be examined, found indisputable evidence of great variations in climate. The vegetation which resulted in the coal measures could have grown only in a sub-tropical climate, while over these are vast remains of ice-worn boulders and scratched rocks which obviously have been left by ice existing under polar conditions. Such records were not found only in one region, but cropped up in juxtaposition in many parts of the world. Remains of sub-tropical vegetation were found in Spitzbergen, and remains of an extensive ice-sheet moving at sea-level from the south were clearly recognized in central and northern India. At first it was simply noticed that the older fossils generally indicated a warmer climate, and it was considered that the early climate of a globe cooling from the molten state would be warm and moist, and so account for the observed conditions. It was recognized that the ice remains were relatively recent, and so far as a cause for the Ice Age was sought it was considered that astronomical changes would be sufficient. It was only when geologists began to find records of ice ages far anterior to the Carboniferous Age, and astronomers proved by incontrovertible observations and calculations that changes in the earth’s orbit, or its inclination to that orbit, could not account for the ice ages, that the importance and inexplicability of the geological evidence for changes of climate came to be clearly recognized.