130 ALFRED W. G. WILSON 



considerably with the seasons, being a little higher in late spring 

 or early summer than at any other time. The level of Lake 

 Ontario also changes considerably during a season. Both of 

 these factors may have some bearing on the formation of the 

 terraces and bars. The changes in level due to the larger seiche 

 waves must occasionally be even greater than these seasonal 

 changes. None of the forms show any evidence which could be 

 interpreted as being due to these seasonal or periodical changes 

 in level. 



In a previous paragraph a detailed description was given of 

 the process by which small cusps were produced along a shore. 

 Under the continued action of waves of moderate amplitude the 

 dimensions of these small forms would gradually increase, and 

 eventually they would reach a size which could easily control 

 the shore currents and wave direction of even moderate storms. 

 In the present instance the bay is completely frozen over from 

 about the middle of November until the first of May. During 

 the season of open water the only effective storms are those 

 which chance to be blowing up or down the bay. To be effec- 

 tive, they must have a constant direction, for a considerable 

 interval of time. Hence, while moderate breezes which generate 

 small waves are frequent, violent storms which can modify the 

 work of all previous lighter winds and waves are rare. When 

 they do come, their first work would be to readjust the shore 

 curves developed during the previous interval. The chances 

 that they would preserve a suitable direction long enough to 

 efface the work of the previous, more or less contsant, but less 

 energetic, storms are very slight. The construction of the small 

 triangular terrace may in part be attributed to the leveling 

 action of some such storms as these. In all observed cases, 

 although the terrace under the triangular lagoon had a slight 

 slope outward, its slope was not so great as that of the adjacent 

 shore a little distance on either side of the sand spit ; from which 

 it is inferred that there had been some filling. Whether such 

 a process could produce a very much larg'er terrace than those 

 noted is uncertain. In other cases the portion of the terrace 

 included between the bars may have been partly filled in by the 



