STJMMAR^^^^^^^^^^^^H 499 



and other obstructions, whether natural or artifieiaL It is also shown 

 by certain constructive features of tlie shorelines already described above. 



This systematic resultant movement toward the east and west ends of 

 the lakes respectively, from distinct nodal zones, is seen to be directly 

 associated with the size of the storm waves. In the case of lake Ontario, 

 for instance, and the same is true of lake Erie, storms from the south- 

 west will roll waves of the maximum size on the northeast shores of the 

 lake, the wind and waves having free sweep toward this section over the 

 widest part of the lake. Similarly storms from the southeast will roll 

 maximum waves toward the northwest shore of the lake. It is these 

 storm waves with the associated longshore currents which perform the 

 maximum amount of transportation and are the cause of the resultant 

 shifting movements in the directions indicated. 



Not only from actual observation may the waves be seen to be greater 

 at the eastern and western ends of the lakes than toward the middle 

 zone at times when storms are blowing toward one or the other end of 

 either lake, but the greater power of these waves is well shown in the 

 height and character of the storm beaches along the shore. Along the 

 middle of the north and south shores of both lakes the storm beaches of 

 coarser debris lie about 6 feet above water level. At the eastern and 

 western ends of the lakes they lie about 15 fefct above the same water 

 level, in the case of lake Ontario at least, and probably of lake Erie, 

 being a little higher at the east than at the west. 



Again, at or near the middle of the lake shores, below the storm 

 beaches, there is a large accumulation of finer pebbles, gravel, and sand. 

 At the ends of the lakes — this is particularly well shown in New York 

 state at the east end of Ontario — the entire beach is at times made up of 

 very coarse materials, the finer having been rolled out below calm water 

 level. 



Summary: Place in Cycle op Shore Development 



At the present time, on both lakes, all the minor and many of the 

 major irregularities of the initial shorelines have been corrected, in part 

 by cutting back, in part by the construction of bars and barriers. The 

 present shorelines as a whole are graded, though here and there are sec- 

 tions, partly rock-bound coast, where shore processes have not yet been 

 able to complete the grading. Between the many barriers and the main- 

 sand and delta deposits. Except in the few localities where the shore is 

 rock-bound, the fronts of the sea-clifEs are gently curved, and over large 

 sections they are often nearly straight. Even behind the rock-bound 

 shores the cliffs have gently curved and often graded fronts, but there is 

 usually an ungraded beach between their front and the water's edge, or 



