Funding for this research was provided by the Coastal and Marine Geology Program of the U.S. Geological Survey and the Massachusetts Office of Coastal Zone Management. We wish to thank Anthony Wilbur, Bruce Carlisle, and Daniel Sampson from CZM for their collaboration in this project. We thank the captains and crews of the R/V Megan T. Miller, R/V Rafael, and R/V Connecticut for their expertise during data collection. Assistance in the field was provided by USGS personnel including Sandy Baldwin, Emile Bergeron, Dann Blackwood, Brian Buczkowski, William Danforth, David Foster, Emily Himmelstoss, Barry Irwin, Thomas O’Brien, Elizabeth Pendleton, and Charles Worley; student interns Maiana Hanshaw (Duke University), and Ankur Agarwala (City University of New York) provided assistance during surveys 06012 and 07002.