498 A. ^V. G. WILSON shoreline studies on ONTARIO AND ERIE 



waves and confines it to the portion of the wave zone beyond the ice-foot, 

 still it facilitates shore erosion in another way. During warm days in 

 winter, particularly in the case of cliffs facing south, local thawing takes 

 place and jjroduces small landslides. The material thus loosened slides 

 down the cliff face upon the shore ice. During early spring, before the 

 shore ice melts, this action is accentuated and local washouts often carry 

 great quantities of waste out upon the ice. Then with the opening of 

 the lake much of this ice, with its load of debris, is floated off by the 

 waves and is transported a considerable distance before it melts and 

 loses its load. In this way much coarse waste is being moved along the 

 shore, and no inconsiderable portion must find its way out into the deeper 

 waters of the lake, there to be deposited with the finer silts and clays. 



Particularly during the early spring the waters of the lakes in a belt 

 along the shore and for a mile or more in width assume a whitish appear- 

 ance, owing to the fine materials suspended in the water, usually clay 

 derived from the till along the shores. In the case of lake Erie, which 

 is much shallower than lake Ontario, the suspended clay is always to be 

 seen along the sliore belt of water, but in Ontario the water usually clears 

 in the late spring and remains clear until late in September. This finer 

 material miist be moved a considerable distance before being deposited, 

 and comes within the zone of action of the body currents, as also does 

 the floating ice and the materials it transports. 



In the shifting of tlie materials along the shores of the lakes locally 

 they are being moved now in one direction, now in the other, according 

 to the wind direction. It is foimd, however, that a single great storm 

 will undo the work of many previous gentler winds. A study of the 

 transportation conditions along the shores of both lakes shows that two 

 distinct resultant shifting movements may be recognized on each lake. 

 On the north shore of lake Ontario it will be found that in the vicinity 

 of Whitby there is a division point west of which the resultant shifting 

 movement is westward, and east of it the resultant movement is eastward. 

 The corresponding point on the south shore of the lake lies somewhat to 

 the west of Charlotte. On lake Erie the nodal points are located near 

 Port Stanley on the north shore and Ashtabula on the south. In this 

 lake, at the west end, the presence of point Pelee and the adjacent islands 

 complicates matters somewhat, and we find in the portion of the lake 

 west of tlie point a slight modification of the general system of move- 

 ment. The general eastward and westward shifting of the waste at the 

 east and west ends of the lakes is shown both by the transportation of 

 certain well recognized materials, such as fossils from laiown horizons, 

 and also by the manner in which the waste accumulates around docks 

 land behind them occur marshes and lagoons partly filled by wind-blown 



