80 



AN AMERICAN GEOLOGICAL RAILWAY GUIDE. (N.Y.) 



the lake. After rising again it forms a beautiful coping of the Hamilton group for miles above 

 Taughannock. See the description of the 10 b. Tully limestone. 



83. This is one of the best localities of the Hamilton group which we know. South of Ludlow- 

 ville the 10 c. Genesee shale appears above the Tully limestone. It is uniformly black, of a slaty 

 structure, fine grained, a hard and brittle mud rock, its edges resisting the weather, but its surface 

 when exposed falling into pieces. You get a good section of the base of the Portage here. There 

 is a well marked dividing line here between the Genesee and Portage, being a sandstone 2 or 3 feet 

 thick, very compact and solid, with its under surface filled with f ucoids raised in relief, one or two 

 inches long, with their ends depressed. The eye readily follows it as it dips toward the water. 



84. Every part of the Portage group can be inspected in the ravines and water falls in the 

 vicinity of Ithaca. 



85. There is a glen here, one mile southeast from the station, quite equal to that at Watkins. It 

 is also in the Portage. See Note 86. 



86. Watkins Glen is in the 11 a. Portage. It is a great wonder and very beautiful. There is a 

 grand view of the chasm in crossing the bridce over it at Glen Bridge on the Syracuse, Geneva & 

 Corning Railroad. The gulfs on that road are perfectly characteristic of the Portage group. 



