F2 Big Bend Drowned Karst. Rugged shoreline, 

 rocky bottoms, very wide shallows area, 

 clear water, extensive seagrass beds and 

 marshes, high fish production, extensive 

 oyster bars. 



F3 Apalachicola Cuspate Delta. Smooth sand 

 beaches, mud-bottomed bays, turbid water, 

 barrier islands present, little or no seagrass. 



F4 North Central Gulf Coast. White sand 

 beaches, clear water, extensive dune system, 

 and barrier island system. High-energy 

 beaches compared to others of the Gulf 

 Coast. 



F5 Mississippi Delta. Extensive marsh systems, 

 barrier island system, sediments silty, silt 

 terrigenous, water turbid, very extensive 

 shallows area, extensive influence from Mis- 

 sissippi River. 



F6 Strandplain-Chenier Plain System. Extensive 

 marsh system, freshwater inflow from several 

 small river systems, but lacking direct influ- 

 ence from Mississippi; cheniers present. 



F7 Texas Barrier Island System. Extensive lagoon 

 system formed by drowned rivermouths and 

 barrier islands, freshwater inflow regular on 

 upper coast to limited with hypersaline con- 

 dition on lower coast, marshes common along 

 upper coast, submerged grass beds common 

 along lower coast, barrier islands of sand. 



G U.S. Southwest Pacific Coast . This division is 

 affected by the California Current. 



Gl Southern California. Fairly smooth coast- 

 line with a few large islands, both low and 

 high-cliffed beaches which are mainly sandy 

 with a few rocky promontories, sporadic 

 seasonal high freshwater inflow, but generally 

 low to no freshwater inflow, extensive algal 

 communities, kelp beds. 



G2 Central California. High-cliffed beaches, 

 mostly rocky but some sandy with a high 

 frequency of pocket beaches in some areas, 

 moderate freshwater inflow, extensive algal 

 communities, kelp beds. 



G3 San Francisco Bay. Highly protected from 



marine influence, some low-cliffed beaches, 

 but mostly low-lying mudflats with a few 

 pocket beaches and marshes, moderate fresh- 

 water influence. 



H U.S. Northwest Pacific Coast. The branching 

 of the Aleutian Current into the Alaska and 

 California Currents occurs off this portion of 

 the coast. 



HI Pacific Northwest. High-cliffed beaches 

 mainly with numerous pocket beaches but a 

 few extensive sandy or rocky beaches; in the 

 northern part are lower rocky coastal flats, 

 moderately dissected coastline, cool water 

 temperatures, high freshwater inflow, numer- 

 ous rocky islands, small bays, and estuary 

 systems with mudflats and eelgrass beds. 



H2 Columbia River Estuary. Separated mainly 

 due to high freshwater inflow generated far 

 inland, extensive inland marsh complex. 



H3 Puget Sound. Relatively protected from di- 

 rect marine influence by Olympic Peninsula, 

 highly complex coastline with numerous 

 islands, high freshwater inflow. 



I P acific Insular . This division is affected by 

 the North and South Equatorial Currents 

 and by the Equatorial Counter Current. 



II Hawaii. Tropical volcanic islands rising 

 sharply from ocean, coral reefs, high wet 

 islands and low dry islands, several species of 

 endemic fauna and flora. 



12 Guam, the Pacific Trust Territories, and 

 Other U.S. Claimed and Administered Is- 

 lands. Tropical islands, some having moun- 

 tains, some with upthrust limestone plateaus, 

 and several with wide sandy beaches and ex- 

 tensive coral reefs, or some combination of 

 the above, all lying north of the equator; 

 includes high wet islands and low dry islands, 

 some of which receive very intense storm 

 activity. 



13 American Samoa and Other U.S. Claimed 

 and Administered Islands. Tropical and sub- 

 tropical islands south of the equator, a few 

 with mountains, but most with low sandy 

 beaches with extensive coral reefs; includes 



