THEORY OF ORIGIN OF BAY OF QUINTE 235 



rocks, and that there are but little differences in height between the op- 

 posite sides. This relation holds systematically throughout the whole 

 region. Again, where the Napanee river enters the Black River cuesta 

 (this is also true of all the others crossing the cuesta) the escarpments 

 on either side are of equal height, and, so far as could be determined, of 

 precisely the same rock (actual identification of individual beds made 

 elsewhere was not attempted here). The escarpment on the southeast 

 is perfectly continuous to the vicinity of the inlet of Hay bay, where it 

 gradually lowers to water-level. Throughout its course it retains nearly 

 the same character, the rocks dipping away from the cuesta front. The 

 opposite side of the valley gradually assumes a more graded slope, and 

 although the basset edges of the strata are exposed, the general slope is 

 very much gentler in the vicinity of the bay of Quinte than it is farther 

 inland. On the opposite side of the bay the corresponding part of the 

 cuesta (west of the Long reach) exhibits features identical with the por- 

 tion of the cuesta to the east of the Long reach. The slight difference 

 in height between the western and eastern sides of the Long reach is 

 apparently associated with the character and dip of the rocks. 



The block-fault theory to account for the origin of the zigzag course of 

 these valleys is regarded by the writer as at present untenable, because 

 there is no known evidence in its support, and it is not necessary to as- 

 sume it to explain the relations of the various valle3 r s and escarpments. 

 The limestone rocks throughout the w r hole region are extensively jointed. 

 In a very few cases there has been a slight local movement along the 

 joint planes. In no instance has the writer noted a displacement of 

 over 6 inches in a vertical direction. The direction of the master joint 

 fractures is intimately associated with the trend of all the master val- 

 leys, though the modern post-Glacial channels are independent of them. 

 It is quite probable that they, to a large extent, controlled the direction 

 of the drainage of the area subsequent to the peneplanation of the lime- 

 stones. It is not improbable that much of the drainage was at first sub- 

 terranean along the line of the master fractures. Indeed, in one instance 

 (Perch creek) the present stream flows along a joint fracture under- 

 ground for a distance of nearly a mile. r J he intimate relation between 

 the jointing and the valley sides is well shown in the cliff front along 

 the west side of the Long reach, where, when considered in detail, it is 

 found that systematically the slight salients and reentrants of the cliff 

 are the obtuse intersections of joint fissures. The distances between 

 these local salients are remarkably uniform alongt he whole 9 miles 

 of cliff, producing a scrolled appearance. These master joints with their 

 associated valleys and the parallel systems of valleys of similar trend 



XXXI— Bull. Geol. Soc. Am., Vol. 15, 1903 



