1889-90.] THE FORMATION OF TORONTO ISLAND. 245 



Another place I visited last summer, viz.: Irondequoit Bay, near 

 Rochester, presents a similar feature. Mr. Hind calls attention to it in 

 1854. He says that the opening was then ^ of a mile farther west than 

 it was formerly, and was becoming shallower. 



The mouth of the Aux Sables, in Lake Huron, presents a remarkable 

 illustration of the onward progress of a beach in the direction of the 

 prevailing winds. 



Rondeau Harbor, in Lake Erie, is almost a fac simile of Toronto 

 Harbor, and many other examples will occur to you on a little reflection. 



If I had time, I would like to call attention to the formation of the 

 marsh. In the early history of the Don, no doubt, it poured its waters 

 directly into the lake, while the spur, shown in Figure V., was in its 

 infancy, and, at the time it was following Greeley's advice under the 

 powerful influence of the easterly storms, the Don was also trying to 

 obey the same injunction by turning, if not its face, at least its mouth 

 toward the west. But the embryo Island grew more rapidly and soon 

 overhauled the Don, and after a lengthened period of high lake level 

 during which time the young giant was working unseen, came a period 

 of low level, when the Don found its progress menaced by the spit of 

 sand running northward to near the site of the old windmill. I have ex- 

 amined various maps of Toronto for the purpose of obtaining light on 

 this part of my subject. The earliest is Bouchette's, which was made in 

 1793. This shows that the bar running northward had entirely closed 

 the present mouth of the Don, and that another mouth existed about 

 halfway between the mainland and the present gap. At this time, I 

 believe, began the deposits which formed the marsh. 



Mr. Lawson, tea merchant, King Street, informs me that he remembers 

 both mouths, the latter being called the big mouth. 



Before the Island afforded the protection it does at present these 

 mouths may have been constantly shifting, and at times both may have 

 been closed up. Indeed, some writers tell us distinctly that such has 

 been the case, and that the water of the Don had no visible out-let, but 

 made its way out by filtration through the bar. At such a time sedi- 

 mentation would go on rapidly. 



This is pretty much my own theory — at least I don't saddle it on any 

 one else, though others may have a prior claim to it. 



However interesting the subject of the Island formation may be to the 

 scientist, Island preservation is of far greater interest to the financier and 

 business man of Toronto. The reports that reach us of the destruction 

 going on at the east end of the Island are of an alarming character, and 

 it behooves our city guardians to take steps for its preservation before 

 our beautiful Island vanishes from our sisfht. 



