Geology of Seneca County. 67 



reminds one of a moraine ridge : the material where exposed 

 being till. 



At Ovid village there are several drift hills, taking more or less 

 the form of ridges (not N-S). Some six or seven miles S. E. of 

 the village there are a number of till ridges running approxi- 

 mately N. W. — S. E.; with a general excess of drift material 

 along the eastward slope of the country. 



Ravines. 



The most striking and beautiful natural features of this region 

 are the ravines, formed by the rapid descent of a great number 

 of short streams to the lakes on each side. They are, of course, 

 of post-glacial origin, and the comparative shortness of their 

 existence is seen in the retention of vertical sides, in the shales 

 equally with the sandstones. The joints traverse all the forma- 

 tions alike, from the Corniferous limestone upward; being, for 

 the two main directions, N. 20°-30° W., and N. 75°-85° E., and 

 nearly vertical ; these joint planes often delimit the entire wall 

 of a glen, aided by minor and less constant ones. Their effect 

 upon the rock scenery is shown in the views of Taughannock and 

 Lodi glens, and King's. Ferry cliff. (Figs. 4, 5, 6.) 



The height of the unbroken fall of water at Taughannock is 

 given at 215 feet. Until recently it fell over a straight edge of 

 rock, but this has been broken in the manner shown in the view. 

 There is a considerable and picturesque fall just above the main 

 one, but concealed from sight, 'i his, being the highest fall of 

 water in the State (Niagara = 165 feet), should not pass unmen- 

 tioned, although it lies a mile or two outside of the boundaries of 

 Seneca county. 



A still more remarkable effect is produced where the stream 

 falls over the Tully limestone, with a good thickness of Hamilton 

 shale beneath. In such cases the stream is often hardly more 

 than a sloping ditch in the field above, and would attract no 

 attention ; it has been unable to excavate the limestone. Its fall 

 is most unexpected; the limestone is broken into a square face, 

 jutting cornice-like over a deep jug-like chasm hollowed in the shale 

 beneath. This is repeated in many streams on the Cayuga lake 

 side of the county. The type for the Portage formation is a high 

 vertical wall, as at Taughannock, with a small ravine above 



