Figure 7. Map showing the coastal plain unconformity offshore of Fire Island, New York, 2011. Regional bathymetric contours are in meters (m) below the North American Vertical Datum of 1988 (NAVD 88). The inset map shows the location of the seismic-reflection profiles where subbottom penetration and resolution allowed identification of the coastal plain unconformity. In addition to chirp profiles collected in 2011, this grid includes reprocessed boomer and sparker data collected by the U.S. Geological Survey in 1996 and 1997 (Foster and others, 1999). The relatively sparse seismic-reflection data coverage yields a generalized, regional surface, with less resolution than other maps presented.