LAKE CHAMPLAIN. 18 L 



more particularly Lake Champlain, since it is there that 

 we have an approximation of the Apalachian chain to the 

 primitive rocks which form the northern brim of the St. 

 Lawrence basin, and unite with the intermediate belt on 

 the north shore of Lake Superior. 



Dr. Emmons* estimates the length of the valley of 

 Lake Champlain at 180 miles, and its average width 

 at about 20. Its bed is most depressed between West 

 Point, Burlington, and Port Kent, where its soundings 

 reach 600 feet, or 500 below the surface of the ocean. f 

 It is in fact a deep chasm with a very abrupt slope 

 on the western side, and a more gradual one on the 

 eastern bank. The direction of the lake is north and 

 south ; it opens into the St. Lawrence basin on the north, 

 and the valley of the Mohawk crosses its axis at some 

 distance on the south. The summit level of the canal 

 which connects it to the Hudson is only 147 feet above 

 the tide ; and a depression to that amount would cause 

 the waters of the ocean to flow through it from New 

 York Sound into the Gulf of St. Lawrence. 



The New York highlands, bounded by Lake Champlain, 

 the St. Lawrence, and Lake Ontario, are formed of pri- 

 mitive granite, hypersthene, and limestone rocks, which 



* New York Geol. Survey. 



f The lake lies, as has been stated in a preceding page, 93 feet 

 above the tidal waters of the St. Lawrence : hence the fall of the 

 St. John or Richelieu River, which discharges its waters just above 

 the tidal level, maybe estimated at 10 inches in the mile; and the 

 descent of the St. Lawrence from Lake Ontario, excluding the com- 

 paratively currentless expansions of the Thousand Islands' Lake and 

 Lake St. Francis, is nearly in the same ratio. These facts may aid in 

 the calculation of the inclination of the beds of similar rivers. With 

 the same view, I may add that the fall of the St. Lawrence between 

 Kingston, at the outlet of Lake Ontario, and Montreal is 220 feet, in 

 a distance of 160 geographical miles in a straight line, of which a 

 considerable part is lake-way, which gives an average of 16 inches in 

 the mile. 



