NE-SAW-JE-WON 



Photo by Michigan Department of Conservation 



PLATE 3.— BEACH ON MACKINAC ISLAND 



LOOKING SOUTH FROM BRITISH LANDING. SHOWS CHARACTERISTICS OF A 



MODERN BEACH. STEP NOTCHES IN BACKGROUND ARE SHORES OF THE 



NIPISSING AND ALGONQUIN LAKES. 



shore lines of lakes are being straightened to smooth curves, 

 as waves and currents build bars, hooks and spits across the 

 coastal indentations, making lagoons which in time become 

 swamps and then flat muck-lands. Sand and gravel are left 

 along the lake beaches, but the finer sediments are carried 

 farther from shore, and the very finest muds are deposited in 

 deep water. The manner of settling of these most-finely- 

 ground muds supplies an interesting geological clock by which 

 to actually measure in years the rate of accumulation of these 

 sediments; and from their thickness can be derived an ap- 

 proximate age for the lake in which they were deposited. In 

 the summer time when sediments are being washed into the 

 lake, the coarser of the fine muds settle to the bottom rather 



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