<descriptor thcode="62"><thesaurus thcode="62" name="Coastal and Marine Ecological Classification Standard" scope="Categories of ecosystems for coastal, estuarine, and marine environments." creator="FGDC" rights="public domain" date="2017-05-10" codetype="alpha" prefix="cmecs" uri="https://www2.usgs.gov/science/CMECS" tblname="cmecs" root_code="root" contact="pschweitzer"><category><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/></category><altlabel><altlabel>CMECS</altlabel><altlabel>CMECS</altlabel><altlabel>Coastal and Marine Ecological Classification Standard (CMECS)</altlabel><altlabel>Coastal and Marine Ecological Classification Standard (CMECS)</altlabel></altlabel></thesaurus><term thcode="62" code="SC-344" name="Clam Hash" parent="SC-321" scope="Substrate Group: Shell Hash (with a median particle size of 2 millimeters to &lt; 64 millimeters) that is primarily composed of loose clam shells and shell bits."/><bt><term thcode="62" code="SC-321" name="Shell Hash" parent="SC-306" scope="Substrate Subclass: Surface substrate layers are dominated by loose shell accumulations with a median particle size of 2 millimeters to &lt; 64 millimeters (Granules and Pebbles). ..."/><term thcode="62" code="SC-306" name="Shell Substrate" parent="SC-301" scope="Substrate Class: Biogenic Substrate that is primarily composed of shells or shell particles. Most (but not all) shell-builders are mollusks."/><term thcode="62" code="SC-301" name="Biogenic Substrate" parent="SC-C003" scope="Substrate Origin: Substrates where percent cover of non-living Biogenic Substrate exceeds percent cover of both Geologic Substrate and Anthropogenic Substrates, when all are considered separately. ..."/><term thcode="62" code="SC-C003" name="Substrate" parent="root"/><term thcode="62" code="root" name="CMECS" scope="Coastal and Marine Ecological Classification Standard: Category terms encompassing waters from the head of tide or inland incursion of ocean salinity to the splash zone of the coasts to the deepest portions of the oceans and the deep waters of the Great Lakes."/></bt><nt><term thcode="62" code="SC-361" name="&lt;i&gt;Coquina&lt;/i&gt; Hash" parent="SC-344" scope="Substrate Subgroup: Shell Hash (with a median particle size of 2 millimeters to &lt; 64 millimeters) that is primarily composed of loose Coquina shells and shell bits."/></nt></descriptor>