This CD-ROM contains digital high resolution sidescan sonar data collected during the USGS Cruise 97009 aboard the R/V MS MS Coastal. This CD-ROM (Compact Disc-Read Only Memory) has been produced in accordance with the ISO 9660 CD-ROM Standard and is therefore capable of being read on any computing platform that has appropriate CD-ROM driver software installed. Access to the data and information contained on this CD-ROM was developed using the HyperText Markup Language (HTML) utilized by the World Wide Web (WWW) project. Development of the CD-ROM documentation and user interface in HTML allows a user to access the information by using a variety of WWW information browsers (i.e. NCSA Mosaic, Netscape) to facilitate browsing and locating information and data. To access the information contained on this disk with a WWW client browser, open the file 'index.htm' at the top level directory of this CD-ROM with your selected browser. The HTML documentation is written utilizing some HTML 3.0 enhancements. The disk should be viewable by all WWW browsers but may not properly format on some older WWW browsers. Also, some links to USGS collaborators are available on this CD-ROM. These links are only accessible if access to the Internet is available during browsing of the CD-ROM. The archived sidescan data may be downloaded and processed. There is software available on this CD-ROM for viewing the individual swaths using any computer system running the UNIX operating system.

The U.S. Geological Survey (USGS), in cooperation with the Connecticut Department of Environmental Protection and National Oceanic and Atmospheric Administration (NOAA), is producing detailed geologic maps of the coastal sea floor. Imagery, originally collected by NOAA for charting purposes, provides a fundamental framework for research and management activities along this part of Long Island Sound, shows the composition and terrain of the seabed, and provides information on sediment transport and benthic habitat. Interpretive data layers were derived from the multibeam echo-sounder data and sidescan-sonar data collected north of Orient Point, New York. During April 2010, bottom photographs and surficial sediment data were acquired as part of a USGS ground-truth reconnaissance survey. For more information on the ground-truth survey see http://quashnet.er.usgs.gov/data/2010/10010/.

In 2010, the U.S. Geological Survey in Woods Hole, MA and St. Petersburg, FL, in partnership with the U.S. Army Corps of Engineers, Mobile District conducted geologic mapping to characterize the seafloor and shallow subsurface stratigraphy offshore of the Gulf Islands of Mississippi. The mapping was carried out during two cruises in March, 2010 on the R/V Tommy Munro of Biloxi, MS. Data were acquired with the following equipment: an SEA Ltd SwathPlus interferometric sonar (both 234 kHz and 468 kHz systems), a Klein 3000 and a Klein 3900 dual frequency sidescan-sonar, and an Edgetech 512i chirp subbottom profiling system. The long-term goal of this mapping effort is to produce high-quality, high-resolution geologic maps and geophysical interpretations that can be utilized to identify sand resources within the region and better understand the Holocene evolution and anticipate future changes in this coastal system. More information on the field work can be accessed from the Woods Hole Coastal and Marine Science Center Field Activity webpage https://cmgds.marine.usgs.gov/fan_info.php?fan=2010-012-FA or the St. Petersburg Coastal and Marine Geology InfoBank https://walrus.wr.usgs.gov/infobank/m/m210gm/html/m-2-10-gm.meta.html.

These data are high-resolution acoustic backscatter measurements of the seafloor from Boston Harbor and the harbor approaches, Massachusetts. Approximately 170 km square of sidescan sonar data were collected by the National Oceanic and Atmospheric Administration (NOAA) Ship Whiting in 2000 and 2001 and reprocessed by the Massachusetts Office of Coastal Zone Management (CZM) and the U.S. Geological Survey (USGS).

The U.S. Geological Survey, in cooperation with the National Oceanic and Atmospheric Administration and the Connecticut Department of Environmental Protection, has produced detailed geologic maps of the sea floor in Long Island Sound, a major East Coast estuary surrounded by the most densely populated region of the United States. These studies have built upon cooperative research with the State of Connecticut that was initiated in 1982. The current phase of this research program is directed toward studies of sea-floor sediment distribution, processes that control sediment distribution, nearshore environmental concerns, and the relation of benthic community structures to the sea-floor geology. Anthropogenic wastes, toxic chemicals, and changes in land-use patterns resulting from residential, commercial, and recreational development have stressed the environment of the Sound, causing degradation and potential loss of benthic habitats (Koppelman and others, 1976; Long Island Sound Study, 1994). Detailed maps of the sea floor are needed to help evaluate the extent of adverse impacts and to help manage resources wisely in the future. Therefore, in a continuing effort to better understand Long Island Sound, we have constructed and interpreted sidescan sonar mosaics (complete-coverage acoustic images of the sea floor) within specific areas of special interest (Poppe and Polloni, 1998; fig. 1). The mosaic presented herein covers a 41.1 km2 of the sea floor in north-central Long Island Sound off Branford, Connecticut. The mosaics and their interpretations serve many purposes, including: (1) defining the geological variability of the sea floor, which is one of the primary controls of benthic habitat diversity; (2) improving our understanding of the processes that control the distribution and transport of bottom sediments and the distribution of benthic habitats and associated infaunal community structures; and (3) providing a detailed framework for future research, monitoring, and management activities. The sidescan sonar mosaics also serve as base maps for subsequent sedimentological, geochemical, and biological observations, because precise information on environmental setting is important for selection of sampling sites and for accurate interpretation of point measurements.