310 



THE CANADIAN NATURALIST. 



[Vol. X. 



the lake, of course, favor the thickening of the soil near the sur- 

 face, when perhaps the succeeding season will be accompanied bj 

 low water, with the consequent distribution of the sediments in 

 only the deeper portions of the area. 



Lake Fluctuations. — In order to ascertain what proportion of 

 the elevation of the bottom of the swamp was due to the sedi- 

 ments. I succeeded in getting some of the records of the fluctu- 

 ations of the lake levels. In a Smithsonian contribution Col. 

 Whittlesea has published a more or less complete register of the 

 fluctuation of Lake Ontario at the port of Oswego between the 

 years 1815 and 1857. The earliest of these records begins in 

 1815 and is continued for the next twelve years, during which 

 time the annual fluctuation was very considerable, the extremes 

 being as much as 4.5 feet. From 1840 to 1853 the maximum 

 difi"erence of levels was only two feet; while that from 1859 to 

 1873 (obtained from other records) was 2.8 feet. 



The question arose whether the lands were rising (or water 

 sinking) or not. At Oswego the mean height of the water 

 between 1840 and 1853 was about nine-tenths of a foot higher 

 than between 1815 and 1827. As the records obtained from 1859 

 to 1873 are not from same datum I cannot compare them with 

 previous years. But if we take the heights from 1859 to 1866 

 inclusive, and those from 1867 to 1873 inclusive we find that 

 during the later period, at Oswego, the waters were about nine- 

 tenths of a foot lower. The table of fluctuations (obtained from 

 Captain Fairgrieve, of Hamilton) for Toronto Harbor shows that 

 the mean height of the water between 1874 and 1865 was one 

 foot lower than that between 1864 and 1854 inclusive. In com- 

 puting these heights the records for two years in each period are 

 incomplete, therefore they have not been included in the calcul- 

 ations. The following are the mean heights of the lake at Toronto 

 above a given datum mark for the years : — 



1854 1 55 feet. 



1865 1.00 feet. 



1866 



1867 1.10 



1868 0.60 



1869 



1870 2.50 



1871 0.83 



1872 — 0.40 



1873 0.40 



1874 1.00 



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