OF DENISON UNIVERSITY. 4I 



present level but has cut a channel through the rocky spur H 

 and S 300 feet wide and 45 feet deep to the present water level. 

 The river here has about 30 feet of water. At K is a rock with 

 25 feet vertical front and at T a rocky projection 45 feet high 

 through which the river has also cut, while there is an open 

 channel 350 feet wide between K and HH obstructed only by a 

 gravel trail 15 feet high extending from K to a low rock expos- 

 ure at KK. 



The rocks S and T are also separated by a channel about 

 250 feet wide presenting vertical walls for a short distance back 

 from the river, and indicated farther south by a depression in 

 the drift filling. 



At FF is a high hill with a rock cliff 25 feet vertical. At 

 uu there is a low rock wall which is extended to the dam at F. 

 Wells in the drift terrace south of w show a buried channel 

 there 50 to 75 feet deep. 



By tracing out the curves and sigmoids indicated by these 

 rocky walls evidence is found for two distinct rock gorges be- 

 sides the one occupied by the present river as shown by the 

 heavy, dotted and broken lines respectively. 



To make these data as clear as possible five sections drawn 

 to scale are presented in Plate II. These sections are taken 

 along the lines bearing the same letters on the map and in the 

 same position. The continuous, interrupted and crossed lines 

 represent the courses of the rocky gorges, while the dotted por- 

 tions represent the estimated depths of the drift filled channels. 

 The line a on both Plates I and II begins at a, as shown by the 

 contours, at the top of a hill 400 feet high ; descends rapidly to 

 L where it drops down the vertical wall 45 feet ; crosses the 

 sand filled channel to the rock m which rises 10 feet ; crosses 

 the channel between m and g; rises 40 feet to the top of g and 

 extends 200 across its top ; drops 40 feet into the channel 

 at n ; rises 45 feet onto the slightly overhanging rock H ; drops 

 again into the vacant channel between H and K ; passes off 

 from K, which is 25 feet high onto a low drift plain which ex- 



