Geologist Alvarez at UC-Berkeley is best known for discovering evidence of the asteroid collision that wiped out the dinosaurs (as recounted in T. Rex and the Crater of Doom
). But much of his career has been spent in the mountains of Assisi, which he calls “the secret archives of Earth history.” For more than three decades, he has studied the rock formations of the central peaks of the Apennines, particularly the Scaglia
limestone, where fossil evidence confirms a mass extinction 65 million years ago—and points to reversals in the planet's magnetic field. His descriptions of the local villages and countryside show flashes of tour-guide charm, and he allows himself a touch of dry humor at rare moments. For the most part, however, his tone is measured and scientific; even riding the surface of an active lava flow is recounted with an oddly dispassionate tone. But readers who appreciate Alvarez's subdued enthusiasm will find a careful unpacking of Italy's geological anomalies (with quick detours to Rome and the Alps) and an intriguing glimpse of Earth's distant past. 8 pages of color and 60 b&w illus. (Aug. 25)
