92 Canadian Record of Science. 



dry weather has affected it to any great extent. Burmg 

 this season of the year and for the summer months, the 

 water draws down about so much each week. This draft 

 may vary a trifle owing to the state of the weather ; if 

 very hot and dry the draft appears greater, which I 

 account for by evaporation and no surface water going in 

 in the shape of rain." 



On the 28th July last I visited the lake for the purpose 

 of ascertaining its depth and temperature, and their bear- 

 ing on the origin of the inflow. The northern and eastern 

 portions of the lake, embracing perhaps one-third of the 

 whole area, were found to be shallow, with a rocky, slowly- 

 shelving bottom. Towards the centre of the lake, the 

 depth drops to about 50 feet. Proceeding thence in a 

 south-westerly direction and at about one-quarter of a 

 mile from the south-westerly shore, the depth is 75 feet ; 

 at 500 feet from this shore it is 99 feet; and at 200 feet 

 from it, 93 feet. This south-western shore, which rises 

 here precipitously to about 25 feet above the water line, 

 appears to form a ragged cliff of probably 125 feet in 

 height, the bottom of which is at the bottom of the lake. 

 Proceeding from this point a quarter of a mile towards 

 the westerly end of the lake and keeping 100 feet from 

 the shore, the depth was found to be 72 feet, whilst 500 

 feet off the extreme west end of the lake the depth was 

 60 feet. The easterly side of the lake towards the southern 

 shore shows considerable depths likewise. At a half of a 

 mile from this end and 400 feet from the south shore, the 

 bottom was reached at 96 feet, but, as this east end is 

 approached, the water somewhat suddenly shallows, and at 

 300 to 400 feet from the shore reeds begin to appear 

 Apparently an area about one mile long by one-quarter to 

 half a mile broad forms a sudden depression in the lake of 

 towards 100 feet in depth, but shallowing to 60 feet as 

 the south-west end of the lake is reached. That it arises 

 from a fault in the Trenton limestone here is very probable, 



