Letters: Volcano's Rebirth

Having been directly involved in research on the posteruptive soils of Mount St. Helens ((ENVIRONMENT, June 15)), I was interested in your observation that the burrowing of pocket gophers has helped mix and enrich the soil. The "bulldozer" effect of the pocket gophers and other small mammals should not be emphasized as or assumed to be the primary reason for the rapid soil development in the area. After the soils were buried by thick layers of pyroclastic flows and debris, complex physical and chemical processes began, aided mainly by the naturally produced acid rain resulting from gases emitted by the mountain....