Author Affiliations +
Geerat J. Vermeij,1 Gregory P. Dietl2
1Department of Geology, University of California at Davis, One Shields Avenue, Davis, California 95616. vermeij@geology.ucdavis.edu
2Department of Geology and Geophysics, Yale University, Post Office Box 208109, New Haven, Connecticut 06520. gregory.dietl@yale.edu