NEW YOKE. 



79 



500 feet or the real depth of the lake, the surface of the 4 a. Trenton limestone being its bottom. 

 It is 180 miles long, 40 miles wide, 492 feet deep and its surface is 245 fe'et above tide water. 



72. Midway between Watertown and Brownville the whole river falls 60 feet in less than half a 

 mile, running in a gorge with high banks. 



73. Tully. The Tully limestone, separating the Hamilton from the Genesee, which is named 

 from this place, is not seen on the railroad, but is found further to the west. The swamp near 

 Preble is supposed to be underlaid by the Tully limestone. 



7'4. Between Syracuse and Jamesville are good natural sections of the 6. Waterlime and 9. 

 Onondaga and Corniferous limestones, many quarries and natural cliffs. Beyond Jamesville observe 

 the transition into the Hamilton group where the high hills begin, the Marcellus shales being deeply 

 excavated. Visit Green Lake, near Jamesville. 



75. The red sandstone of the 5 a. Medina formation is well displayed at Fulton, in Oswego County, 

 where it causes the Oswego Falls and forms the banks and bed of the river above and for half a 

 mile below. The upper layers are covered with Fucoides Harlani, some of them of gigantic size. 



76. The 5 b. Clinton formation is named from this place. 



77. This is one of the best railroads in the State for geological observations. There are many 

 points on the Cayuga Railroad where the junction of the Hamilton with the Tully limestone and of 

 the latter rock with the Genesee shale, and of the Genesee with the Portage group are perfectly seen 

 in juxtaposition. The lake affords every evidence and facility for geological sections. 



78. Cayuga Lake is 40 miles long, 3| miles wide, 390 ft. deep, and its surface is 376 ft. above tide. 



79. The gypsum beds are finely displayed just north of Union Springs, and large quantities are 

 produced for market. South of the town the 9. Upper Helderberg range crosses, and causes an islet 

 m the lake. Its lower layers, the Onondaga limestone, make beautiful quarries. 



80. The low clayey land extending nearly to Levanna is on the 10 a. Marcellus shale. The first 

 rock south of this is the dividing line^ between the Marcellus and Hamilton. 



81. The 10 b. Hamilton presents its first bluff south of Aurora, 20 to 50 feet high, containing 

 numerous fossils. Further south are many others, some of them 100 feet high, extending for 

 miles. Nothing could be finer than these geological sections of the Hamilton. 



82. The Tully limestone first appears at Lake Ridge, from which the station is named. It is the 

 dividing line between the 10 b. Hamilton and the 10 c. Genesee. It dip? as you go south and rises 

 again. This looks like a flexure of the formations, but it is caused by the change in the course of 



