This is a nice time for a history of geology -- there is such a happy symmetry in the moment and almost a mood of celebration as one of the study's oldest and most persistently dubious propositions is redeemed and validated. Of course, the new geology of plate techtonics is still a far cry from Wegener's intuitive vision of a vast, proto-continental land mass broken into drifting chunks. Others from Francis Bacon to Dane Rudhyar have speculated on the jigsaw fit of the continents, to the irate ridicule of the geophysicists, until the debate was effectively settled in 1950 by P. M. S. Blackett, the ""Father of Paleomagnetism,"" in ""the last great pitched battle between the drifters and the antidrifters."" Until roughly the turn of the century there simply weren't the means to make the kinds of measurements required or to assemble appropriate data to substantiate a comprehensive earth theory; only then, with a spectacular evolution of techniques, advances in physics and astronomy and geological specialties, was geology shot by its bootstraps from the upper echelons of natural history to that pinnacle occupied by the physical sciences. As a result, its development hasn't had the philosophical impact or cultural suasion, and consequently doesn't offer the kind of high intellectual drama of, say, the biological sciences as surveyed by Francois Jacob in his Logic of Life (KR, p. 87). But this is a book of comparable quality, and certainly not undramatic, geology always and especially now being a highly inferential and most ingenious business. Dinely writes in a gracefully excited style, though on a level that does call for his appended glossary. Better that than be patronized.