SPECIAL TOPOGRAPHIC FEATURES 221 



Rivers in New York state. — The Bateau channel of the Saint Lawrence 

 river below Kingston is a partly submerged portion of the eastern end 

 of the Twelve Mile reach of the bay of Quinte. The American channel, 

 as will be shown subsequently, is also one of those submerged valleys. 

 Between cape Vincent and Sacketts harbor a number of southwest-flow- 

 ing streams occupy well defined rock valleys. Of these Chaumont river, 

 Perch creek, and the Black river cross the limestone areas in valleys of 

 the first type. Mud creek, Muskalonge creek, and a few other minor 

 streams occupy valleys of the second type. The most important of these 

 streams is the Black river, which to the south of Carthage flows for a 

 long distance in the position of a normal subsequent stream along the 

 lowland between the limestone cuesta and the Adirondack oldland. 

 South of Sacketts harbor there are a number of southwesterly flowing 

 streams all of which head on the upland, and most of which show in 

 parts at least that the valleys which they occupy, though more or less 

 drift-blocked, are of the types here described. A more detailed reference 

 to them is not necessary in the present discussion. 



Enough has already been said to show that on either side of the 

 present Saint Lawrence outlet we have a well marked system of south- 

 west trending rock-walled valleys, with a number of similar rock-walled 

 minor valleys tributary to them and joining them at accordant levels. 



Before describing these valleys more in detail and before discussing 

 their inter-relations and their relation to the Saint Lawrence outlet, it 

 will be well to consider the question of their probable origin and its date. 



ORIGIN OF THE BEDROCK TOPOGRAPHY 



That these valleys are due to normal processes of stream erosion is 

 attested by their form and shape and by the uniform accuracy of the 

 adjustments between tributary and main valleys. North and east of 

 Trenton and west as far as the headwaters of the Trent system, many of 

 these valleys are found more or less occupied by drift deposits. The 

 lowest of these deposits, as shown in the section cut by the Trent river 

 north of Trenton and in numerous other sections along lake Ontario, is 

 a clay till of what is probably the second glacial epoch. This till is 

 overlain by other deposits of several interglacial and glacial epochs re- 

 spectively. Beneath the till, which is rather widespread, the striated 

 and grooved rock surface is frequently found. It is certain that many 

 of the valleys — and thus by inference that all of them, since they are very 

 closely alike in form and adjustment — antedate the ice-sheet which de- 

 posited the lowest till-sheet of central Ontario and produced the striated 

 rock surface. 



