The geological timetable is a thing of shreds and patches, the product of the shifting views of the nineteenth century about the proper subdivision of geological time. Usage is not uniform. Logically the Pleistocene (“most recent”) period includes both Recent time and Quaternary time, which covers the so-called Glacial period. Geology has been developed by men living in the middle latitudes of the Northern Hemisphere. For those leaders of thought the Glacial period is of the past. For a geologically minded penguin of Antarctica the Glacial period is here and now. The truly objective philosopher must agree with the penguin: the earth as a whole is something like halfway through the Glacial period. Land ice now mantles 15,000,000 square kilometers, as against 30,000,000 square kilometers, or 6 per cent, of the earth's surface when the ice-caps were last at . . .