GSA Today
Volume 19, Number 12 (December 2009)

About the cover:
“Darwin’s boulders” in the Atlantic Ocean, Tierra del Fuego. Charles Darwin described this large, barn-shaped boulder in June 1833. See “Enigmatic boulder trains, supraglacial rock avalanches, and the origin of ‘Darwin’s Boulders’ — Tierra del Fuego” by Evenson et al., p. 4–11.