MUCH OF THE geology I once learned is long forgotten, but what remains, indelibly, is an awareness of time, geological time. Much of my work was in the late Devonian, more than three hundred million years ago. That did not long seem strange: it was my familiar working time, full of detailed subdivisions (Frasnian, Famennian, etc.) which were the hours, minutes and seconds of that geological time clock.

Political time, with three– or four-year elections, is fleeting; anthropoid time, with about a twenty-five year turnover, is equally transient. Both are ephemeral events like the life of a butterfly, although that is not to deny that the lifespan of the butterfly is all-important to the butterfly, as it is to the anthropoids and other ephemerids.