Two marine geological surveys were conducted in Long Island Sound, Connecticut and New York, in fall 2017 and spring 2018 by the U.S. Geological Survey (USGS), University of Connecticut, and University of New Haven through the Long Island Sound Mapping and Research Collaborative. Sea-floor images and videos were collected at 210 sampling sites within the survey area, and surficial sediment samples were collected at 179 of the sites. The sediment data and the observations from the images and videos are used to identify sediment texture and sea-floor habitats.

Attributes:

ANALYSIS_ID: An identifier for the sample that is unique to the database. This identifier begins with the assigned multi-letter code GS-, which corresponds to the type of analysis performed on the sample (grain-size analysis), followed by a six-digit number assigned sequentially as samples are registered for analysis.

SAMPLE_ID: The identification value assigned to the sample at the time of collection. This varies from field activity to field activity, and the ID can contain any combination of letters and numbers.

FAN: The serial number assigned to the dataset field activity during which the sample was collected. This value is in the format YYYY-XXX-FA where YYYY is the year, XXX is the number assigned to the activity within the year, and FA indicates Field Activity.

LATITUDE: Latitude coordinate, in decimal degrees (WGS 84), of sample location. South latitude is

recorded as negative values.

LONGITUDE: Longitude coordinate, in decimal degrees (WGS 84), of sample location. West longitude is recorded as negative values.

DEPTH_M: Approximate depth of water in meters at the sample location derived from an unpublished composite bathymetry dataset used by the Long Island Sound Mapping and Research Collaborative.

T_DEPTH: Top depth of the sample below the sediment-water interface in centimeters.aborative project.

B_DEPTH: Bottom depth of the sample below the sediment-water interface in centimeters.

DEVICE: Sampling device used to collect the sample.

DATE COLLECTED: Calendar date based on UTC time indicating when the sample was collected in the format MM/DD/YYYY where MM is the numeric month, DD is the day of the month, and YYYY is the year.

ANALYSIS COMPLETION DATE: Calendar date indicating when analyses on the sample were completed in the format MM/DD/YYYY where MM is the numeric month, DD is the day of the month, and YYYY is the year.

ANALYSIS METHOD: Method used to analyze the sample for grain-size distribution. Grain-size analysis using the HORIBA laser diffraction unit and sieving of the >= -2 phi fraction.

WEIGHT WET SAMPLE (g): Weight of initial sample in grams

GRAVEL (wt%): Gravel content in percent dry weight of the sample. Gravel consists of particles with nominal diameters greater than 2 mm (-1 phi and larger).

SAND (wt%):

Sand content in percent dry weight of the sample. Sand consists of particles with nominal diameters less than 2 mm, but greater than or equal to 0.0625 mm (0 phi through 4 phi, inclusive).

SILT (wt%): Silt content in percent dry weight of the sample. Silt consists of particles with nominal diameters less than 0.0625 mm, but greater than or equal to 0.004 mm (5 phi through 8 phi, inclusive).

CLAY (wt%): Clay content in percent dry weight of the sample. Clay consists of particles with nominal diameters less than 0.004 mm (9 phi and smaller).

CLASSIFICATION (Shepard): Sediment classification based on a rigorous definition (Shepard [1954] as modified by Schlee and Webster [1967], Schlee [1973], and Poppe and others [2005]). In the definitions below, gravel is defined as particles with nominal diameters greater than 2 mm; sand consists of particles with nominal diameters less than 2 mm, but greater than or equal to 0.0625 mm; silt consists of particles with nominal diameters less than 0.0625 mm, but greater than or equal to 0.004 mm; and clay consists of particles with nominal diameters less than 0.004 mm.

The shapefile is a simplified version of the CSV file of the Multisizer analysis results (2017-056-FA_and_2018-018-FA_samples_GS-MS.csv) with fewer attribute fields. Specifically, STDEV, SKEWNESS, KURTOSIS, and the individual phi measurements (e.g., PHI_11) were removed. The shapefile also has two additional attributes, FID and Shape, which have the following descriptions:

Attribute:

Attribute Label: FID

Attribute Definition: Internal feature number.

Attribute Definition Source: Esri

Attribute Domain Values:

Unrepresentable Domain: Sequential unique whole numbers that are automatically

generated.

Attribute:

Attribute Label: Shape

Attribute Definition: Feature geometry.

Attribute Definition Source: Esri

Attribute Domain Values:

Unrepresentable Domain: Coordinates defining the features.

All the other attributes in the shapefile have the same definitions as the CSV file attributes (see the detailed description section for the 2017-056-FA_and_2018-018-FA_samples_GS-MS entity for definitions of the CSV file attributes). Please note that some of the field names were truncated since a shapefile field name can only contain up to 10 characters. The following fields are included in the shapefile: FID, Shape, ANALYSIS_I (truncated field name for ANALYSIS_ID), FIELD_NO, PROJECT, FA_ID, CONTACT, AREA, LATITUDE, LONGITUDE, DEPTH_M, T_DEPTH, B_DEPTH, DEVICE, DATE_COLLE (truncated field name for DATE_COLLECTED), ANALYSIS_C (truncated field name for ANALYSIS_COMPLETION_DATE), WEIGHT, GRAVEL_PCT, SAND_PCT, SILT_PCT, CLAY_PCT, CLASSIFICA (truncated field name for CLASSIFICATION), MEDIAN, MEAN, ANALYST, and COMMENTS.