Contents

04 October 1991
Vol 254, Issue 5028

About The Cover

A cloud pouring over the western face of the Sentinel Range, Ellsworth Mountains, Antarctica. Fission-track analysis of samples from the Vinson Massif, Antarctica's highest mountain (4897 meters; 8 kilometers south of this photo), indicates that the Ellsworth Mountains were uplifted more than 4 kilometers during the Early Cretaceous (between 141 and 117 million years ago) and that at least 1.8 kilometers of relief has persisted since then. See page 92. [Photo by Ed Stump]