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 OFR 2005-1001 Home   /    Procedures    /    East-Coast Database   /    GIS Data Catalog

U.S. Geological Survey Open-File Report 2005-1001
USGS East-Coast Sediment Analysis: Procedures, Database, and GIS Data


Database Visualization

Diagram showing Shephard's Classification scheme
Shepard's Classification Scheme

Those samples for which full grain-size data are available were also assigned classifications based on definitions found in Shepard, F.P., 1954. In displaying the lithologic descriptors, the general ranking principle of the main constituents (e.g. gravel, sand) and modifying constituents (e.g. sandy, silty) follows in order of decreasing coarseness. The sediment classification color assignment is represented by the following legend:



Sediment Classification

Red - sediment whose main phase is gravel (>50%); rocky bottom


Orange - sediment with significant amounts of gravel (>10%, but <50%)


Yellow - sediment whose main phase is sand without significant gravel or mud


Green - sediment with significant (>20%) sand, silt, and clay


Blue - sediments whose main phase is silt (>50%)


Purple - sediments whose main phase is clay (>50%)

Available overview maps of the sediment classes for several selected U.S. Atlantic East Coast regions are available below.  Maps are available in both JPEG image format and Adobe PDF. 
To view the PDF maps, you need Adobe Acrobat Reader. If this is not already installed on your computer, you can download it free by clicking here.  

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