M5 Bering Sea Islands. Volcanic-type islands 

 with pocket beaches, precipitous cliff-type 

 shoreline, backing onto grassy highlands often 

 rising to volcanic peaks of 3,050 m (10,000 

 ft), but may have extensive areas of marshy 

 lowlands and well-developed barrier islands 

 and spits, receiving wave action on all sides 

 from Bering Sea. Ice-influenced in all cases, 

 islands may be ice-locked up to half the year, 

 with extensive ice-scouring. 



N Arctic Alaska. This division is affected by 

 the North Atlantic Littoral Current and the 

 Arctic Basin Gyre. 



Nl Chukchi Coast. Receives wave action from 

 Chukchi Sea, some mountainous coastline, 

 but mostly low-lying, marshy areas, with 

 some areas having extensive barrier islands. 

 Some sounds and inlets protected from wave 

 action. Ice-locked during winter, ice-free 

 during summer, receives extensive ice- 

 scouring. 



N2 Beaufort Coast. Receives wave action from 

 Beaufort Sea, ice-locked during winter, usu- 

 ally ice-free in summer, very extensive ice- 

 scouring. Coastline very low with extensive 

 marshy areas. Some barrier islands. 



Great Lakes. This division is a freshwater 

 area not affected by marine currents. Each 

 lake, however, has complex current patterns 

 of its own. 



01 Lake Superior. Has the most rugged unin- 

 habited and inaccessible shorelands of all the 

 Great Lakes. The shore type of Lake Superior 

 and the St. Marys River varies from the steep 

 rock cliffs of the Pictured Rocks National 

 Lakeshore Area to the sandy beaches of 

 White Fish Bay, Michigan, to the low-lying 

 clay and gravel bluffs near Duluth, Minne- 

 sota, and in Wisconsin to the marshlands of 

 Munuscong Bay, Michigan. Lake Superior 

 and St. Marys River contain major islands 

 and island groups. 



02 Lake Michigan. Large expanse of sand dunes 

 extending almost continuously from the In- 

 diana Dunes National Lakeshore northward 

 to the tip of the Leelanau Peninsula in Mich- 

 igan. They result from the prevailing westerly 



winds that cause an almost continuous wash- 

 ing and separation of shore soil material by 

 wave action. Wide, sandy beaches are often 

 associated with the dune areas, especially 

 during years of low water levels on the Great 

 Lakes. 



03 Lake Huron. Mainly a rock and boulder shore 

 in the northern area with some high bank 

 beaches extending landward into a rolling 

 upland area. From Sand Point in outer Sag- 

 inaw Bay to the most northern part of Huron 

 County, the shore is composed of sandy 

 beaches backed by low dunes and bluffs. 

 This shore type also predominates in Sanilac 

 County. From northern Huron County east 

 and south approximately to the Huron-Sani- 

 lac County line, exposed bedrock and very 

 rocky shorelands replace the sandy shore 

 type. The shorelands of Lake St. Clair are 

 predominantly artificial fill, erodible low 

 plain, and a smaller wetland contingent. 



04 Lake Erie. Eastern Lake Erie has glacial till 

 and raft-shale bluffs. The Pennsylvania por- 

 tion comprises shore bluffs of 15 to 30 m 

 (50 to 100 ft). Bluffs are composed of clay, 

 silt, and granular material with shale bedrock 

 occurring about water level. To the east of 

 Erie Harbor, the shale bedrock is frequently 

 5 to 11 m (15 to 35 ft) above lake level and 

 the upper part of the bluff is composed of 

 silt, clay, and granular material. Sand and 

 gravel beaches up to 46 m (150 ft) wide ex- 

 tend along the toe to the bluffs. The shore- 

 line of western Lake Erie consists mainly of 

 wetlands, low plains, artificial shore types, 

 and low rocky bluffs. Lake Erie is subject to 

 impressive seiches. 



05 Lake Ontario. The U.S. shoreline consists 

 generally of bluffs of glacial material ranging 

 from 6 to 18 m (20 to 60 ft) high. Narrow 

 gravel beaches border the bluffs, which are 

 subject to erosion by wave action. The bluffs 

 are broken in several places by low marshes. 

 The shore in the vicinity of Rochester and 

 Irondequoit is marshy, with sand and gravel 

 barrier beaches separating the marshes and 

 open ponds from the lake. The shoreline 

 from Sodus Bay east to Port Ontario is a 

 series of drumlins and dunes separated by 

 marsh areas. North of the Oswega-Jefferson 



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