124 J. W. SPENCEE ON 



The Iroquois Beach enters New York at Lewistou, on Niagara River, aud extends as 

 far east as Gr^^at Sodus Bay, at only a few miles distant from the modern shore. Thence, 

 it swings round, passes under Cayuga Lake (Gilbert) and skirts an embayment from 26 

 to 35 miles wide, which encloses Oneida Lake, and turns northward to a point about 

 live miles east of Watertown, near Black Eiver Station, where on the side of a great 

 promontory, which may be called Cape Rutland (a spit of Carabro-Silurian limestone, 

 bounding the interesting Rutland Hollow), it bends eastward, aud becomes diffiovilt to 

 follow. I have traced it to a point about twenty-five miles east of Watertown, near 

 Stirling Bush, amongst the Laureutian ridges, upon the flanks of the Adirondacks. 



(3.) Table of differential elevations along the Iroquois Beach. — In the fol- 

 lowing table, all of the elevations were on the summits of the ridges. Sources of error, 

 at each place of observation, occur, owing to variations in height, arising from the former 

 different intensity of wave-action upon the shore, either exposed or protected, and from 

 subsequent washes on or off the beaches ; and along spits, which are generally a little 

 lower than the adjacent barrier-form of the beach. Besides these errors, others arise in the 

 subsequent deductions, on account of taking measurements from the maps. However, as 

 these local errors, incident to each place of observation, do not produce a greater variation 

 in our calculations than a small decimal of a foot per mile, they may be omitted ' : — 



Feet above sea. 



Hamilton 363 (Spencer.) 



Burlington Heights 355 " 



Watertown Station 365 " 



Cook sville Station about 400 " 



Carlton Station 417 



Kingston Koad, at railway crossing, 12 miles east of Toronto 459 '' 



Whitby, 6 miles north of the lake at 507 " 



Colborne Station, 2 miles north of 602 " 



Trenton Station, 2J mile north of 082 " 



Lewiston,N.Y 385 (Gilbert.) 



Rochester 436 " 



Canastota 441 " 



Cleveland 484 



Constantia 489 " 



Richland 563 



Adam's Centre 657 " 



Cape Rutland 700 (Barometer.) 



Great Bend Station, above 685 " 



On Laurentian Islands, near Stirling Bush 067 " 



(4.) Area and depth of the Lake durinu epoch of the Iroquois Be.4ch. — The 

 area of the western portion of lake, as defined by the Iroquois Beach, was not much 

 greater than that of the modern Ontario, except towards the south-eastern portion, as 

 shown on the map. The extension of the lake towards the north-east, between Ottawa 

 River and the foot of the Adirondack Mountains, beyond the limits of the map, was 



' The author's elevations were levelled from the nearest railway stations, the barometer being used only where 

 expressed ; those of Mr. Gilbert were obtained by use of liand levels to adjacent known points. 



