Generally, beach sediments from the eastern coast of Lake Michigan 

 are well-sorted, medium sands. However, there is a tendency for each site 

 to have its own peculiar sediment texture. This texture does not vary 

 appreciably with time except during the time of protection or cover by 

 shore ice. Typically, shore ice and the sampling difficulties associated 

 with it yielded a poorer sorted beach sand as compared to the same site 

 during periods of open water. This is partly due to ice-push activity in 

 the foreshore which mixes sedimentation units, and also due to sediment 

 incorporated in the ice settling down on the beach as melting occurs' on the 

 beach proper. This takes place before breakup of the ice ridges when the 

 beach is still in a zero-energy condition. 



Because sediment parameters were described in previous reports for the 

 first 2 years of the study (Fingleton, 1973; Davis, Fingleton, and 

 Pritchett, 1975), and there were no deviations during the third year, only 

 a general summary is presented in this report. 



Gravel, including cobbles, was abundant at sites 1 and 5, and there 

 was commonly a fair amount of gravel at site 16. Sites 5 and 16 are near 

 Pleistocene till which would provide a source; however, site 1 is on a 

 point (Point Betsie) which contains widespread dune development. Coarse 

 gravel and cobbles which dominate this beach are probably reworked from 

 a Pleistocene source lakeward of the beach. Although gravel is not typical 

 on the beach at site 13, it is common just lakeward of the plunge zone. 

 This site is also adjacent to bluffs of Pleistocene till. 



Nearly all beaches had scattered pebbles or rows of pebbles during most 

 visits. Notable exceptions were sites 4, 6, 9, and 11. All of these sites 

 are in areas of dune development and the northern two (4 and 6) are on Big 

 Sable Point and Little Sable Point which are areas of sediment accumulation. 

 These two sites are among those with relatively fine grained sand. There 

 are three sites (12, 13, and 17) which typically contain a large quantity 

 of granules or very fine gravel. As a result, they are the coarsest of the 

 beaches in the study. The sites are located in areas where a Pleistocene 

 till source is adjacent or nearby. 



There are easily recognizable local factors which control or contribute 

 the textural characteristics at each of the beaches, with the exception of 

 the cobbles at site 1. Backshore sands are somewhat finer grained and bet- 

 ter sorted than foreshore sands which is to be expected because of the com- 

 bination of wind effects and swash dynamics. 



The dynamic and erosional nature of the beaches along eastern Lake 

 Michigan coupled with the tremendously heterogenous source of sediment pro- 

 vided by Pleistocene drift obscures any size-slope relationship described 

 by Bascom (1951) and Shepard (1972) that might exist. All beaches studied 

 are not stable and consequently plots of grain size versus slope show tre- 

 mendous scatter (Davis, 1972; Fingleton, 1973). 



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