Mysteries of Terra Firma

James Lawrence Powell

Read January 2006

Powell's is a perfectly serviceable introduction to thinking about geology. His organizational conceit is that there are three great forces that shape modern geological understanding: time, drift and chance (his words). It's a useful organizational device for a layman: we are all now used to thinking about geological time, but the other two, Powell points out, are also significant. It's difficult, however, to tell two things: just how significant, and whether they are truly independent. Indeed, the theme of drift is but a gentle shell over continental drift (no other kind gets discussed), while chance is mostly a discussion of impacts (of the dinosaur-killing and moon-spawning kinds). The book also has a little difficulty finding just the right balance between science-as-personalities on one side and technical geology on the other, but for the most part it stays in the informal realm, where it is probably of more use: lay readers could use more of this sort of structural presentation of a discipline.