42 BULLETIN OF THE LABORATORIES 



tends to the river at the dam : crosses the river onto the rock . 

 again beyond F. 



Section b shows the river channel between O andP ; the old 

 channel at R ; the rocky spurs S and T separated by the drift 

 channel ; the broad channel between T and uu occupied by the 

 pond u ; the rock wall at uu and the gravel terrace w. 



Section c starts in the river where it enters the map and 

 shows the overhanging wall at X with the high drill covered 

 divide to the rock expose at Y and the low rock wall on the 

 opposite side of the channel ; the lowest point in the drift plain 

 at z and the gravel terrace beyond. 



Section d taken at right angles to the three preceding be- 

 gins at d on a hill 150 feet high, descends a vertical wall 45 feet 

 at b into the channel OO ; crosses the low rock mass m and the 

 channel between m and g ; shows the overhanging character of 

 the narrow gorge between g and c and the elevation at which 

 the river must have began to cut for this channel above the 

 open channel at 00 ; the railroad cut and lastly the high drift 

 covered area between X and Y. 



The section e shows especially the channel between HH 

 and K and the bold front presented to the river by the rock T 

 at a. Similar vertical fronts are presented by the rocks 

 H and S. 



The river throughout its entire length in this gorge is flow- 

 ing on rock bottom. 



Below Toboso, Plate IV, the gorge opens out into a large 

 basin shaped valley which narrows again at Claypole. The 

 canal leaves the river at Toboso and after passing down the 

 Licking valley to Nashport passes through a gap between the 

 rocky hills to the north and enters a great open valley which it 

 follows to the present Muskingum valley at Dresden. 



Beyond Claypole the Licking valley again broadens some 

 what, but rapidly narrows below Irville. At the great curve 

 south of Irville, where the river turns southeast, the B. & O- 

 railroad has made a rock cut on the south side of the river and 



