No. 3.] SPENCER PALAEOZOIC GEOLOGY. 131 



II. — TOPOGRAPHY AND DISTRIBUTION. 



Extending along the southern shores of Lake Ontario, at dis- 

 tances varying from one to a few miles from its waters, there is a 

 ridge of hills, or more pruperly an escarpment, known to geolo- 

 gists as the " Niagara Escarpment," extending from the State of 

 New York into Canada, and entering our country near Queenston, 

 whence the canon of the Niagara Falls has worked backward 

 for several miles. From the Niagara River this rido-e extends 

 westward to the town of Dundas, and thence the trend is a little 

 west of north to Lake Huron and Manitoulin Islands. 



This ranoe everywhere forms a bold feature. Alons; the 

 southern shore of Lake Ontario, the brow is 400 feet above the 

 lake, while near the " Peak," north of Dundas, the height is 520 

 feet, from which place the ascent is gradual as it extends north- 

 ward, until just west of Limehouse, the cliffs have a height of 

 847 feet, whence the plateau gradually rises to 936 feet at 

 Rockwood (on the G. T. Railway), and northward, in Amaranth 

 township, it has an elevation of 1400 feet above Lake Ontario. 

 In its course, south of Lake Ontario, the slope is generally more 

 abrupt than after the range assumes a northerly trend, — the 

 upper portion often forming almost perpendicular cliffs from 100 

 to 250 feet above the rising slope at its base. The brow where 

 the H. & N. W. Railway ascends the mountain (four miles east 

 of Hamilton) is 395 feet, and at the head of James street, 

 Hamilton, it is 388 feet above the lake, while the plateau above 

 gradually rises to 493 feet, five and a half miles south of the 

 former place, and to 485 feet, two miles south of the latter. This 

 height of land forms the watershed between Lakes Ontario and 

 Erie, and from it the country gradually slopes to the latter lake. 



The rocks of this range belong to the various subdivisions of 

 the Niagara Group of the Silurian Age. The Canadian Geolo- 

 gical Survey, many years ago, separated the Niagara and Guelph 

 groups from the overlying Lower Helderberg group, and called 

 these Middle Silurian, whilst the New York geologists placed 

 them all together, and called them Upper Silurian. We will adopt 

 that nomenclature which recognises the rocks of the various 

 groups from the Niagara to the Lower Helderberg (inclusive), as 

 being members, not of the middle or upper, but of the one great 

 Silurian Age, and consider the Lower Silurian formations (Tren- 



