478 A. W. G. WILSON SHORELINE STUDIES ON ONTARIO AND ERIE 



thougli it is extremely probable that one is being built. The nature and 

 persistence of the discharge, however, offers a suggestion as to the results 

 that might be brought about were a large amount of waste supplied to 

 the longshore current before it passes out into deeper waters. 



At Scarboro and Toronto the strongest waves and associated longshore 

 current would come from the east and southeast in former times as now. 

 Because of the marked change in the trend of the coastline, the longshore 

 westbound current would tend to discharge out into the lake at the point 

 where the relatively abrupt change in the direction of the shoreline took 

 place. The cliffs at Scarboro AA^ould supply an exceptional amount of 

 loose debris, much more than is found anywhere else along the north 

 shore. The result would be the construction of a flying spit from Scar- 

 boro waste reaching out into the lake from the point of discharge of the 

 shore current. This spit would gradually increase in length and also 

 tend to broaden. In time it would protect the land adjacent to the 

 mouth of the Don from the eastern storms. Such storms as came from 

 the west would not only be weaker agents of shore process, but would 

 tend to force the debris which the Don was discharging into the lake back 

 into the bay between the flying spit and the shore. In the early history 

 of the lakes and of the bar it seems probable that the greater portion of 

 the debris from the Don, like that from all the other streams up to the 

 present time, was distributed along the shores by the shore processes, and 

 that no distinctive delta was bi;ilt up. In later times the protection 

 afforded by the young Scarboro spit guarded the mouth of the Don from 

 the master storms, and forthwith it began to build up a delta and to aid 

 in the filling of what is now Ashbridge bay during the course of the delta 

 formation. The westward progress of the spit was, however, far more 

 rapid than the Don filling, so that in time the portion that now forms 

 Toronto harbor was built west of the Don mouth. 



At first the bar would be narrow and ridge-like, but as the apex ad- 

 vanced into deeper water its progress westward would be slower, giving 

 time and opportunity for storms from other than the dominant direction 

 to variously modify its apex. The general history of all such spits seems 

 to be that when they reach deeper water the outer end shall be turned 

 shoreward by waves and currents from deeper water offshore. The com- 

 bined action of forward building and shoreward spreading lead, in this as 

 in other cases, to the broadening and hooking of the free end of the spit, 

 and incidentally to the inclosing of a number of lagoons between minor 

 bars built at successive intervals, according as the longshore or transverse 

 processes were the more active, 



