DESCRIPTIONS OF THE FORMATIONS. 25 



This formation establishes the topographical distinction between the lower 

 plain of Canada, in which lie Lake Ontario and Georgian Bay, and the upper 

 plain of the United States, on which lie Lakes Erie, Huron and Michigan. 

 Its terrace crosses Ontario, growing loftier as the thickness of the formation 

 increases northwestward, until it becomes a range of limestone mountain-land, 

 forming the peninsula between Lake Huron and Georgian Bay. It is there broken 

 down in a range of islands, and reappears as a peninsula, just mentioned, cutting 

 off Green Bay from the western shore of Lake Michigan. 



The Niagara and other limestones above it, seem not to have been deposited hi 

 Pennsylvania between the Delaware and Susquehanna rivers, and in Middle 

 Pennsylvania. While the limestones below it are well represented, the Niagara 

 is wanting as a separate formation, and its characteristic fossils are scattered 

 through the Clinton rocks. 



6. Salina, (Onondaga Salt Group.) This is an important group in the State 

 of New York, containing all the gypsum and water-lime, and furnishing all the salt 

 water of the salines of the city of Syracuse, which produce more salt in a small 

 territory than any other in the world. Its soil is excellent for agricultural purposes, 

 forming, with those south of it, including the Hamilton, the garden-region of the 

 State of New York. The whole group is about 700 feet in thickness, and is 

 divided into five deposits, but there are no well defined lines of division between 

 them, except the last two. 



1. The first or lowest is a red shale, showing green spots at the upper part of 

 the mass. The great mass is of a blood red color, fine grained, earthy in fracture, 

 with no regular lines of division, but breaking or crumbling into irregular 

 fragments, and shows but little variation. In several localities the red shale shows 

 numerous green spots, varying from an inch or less to several inches in diameter, 

 which strongly contrast with the red ground on which they are placed. The green 

 color is the result of a chemical change, the peroxide of iron being reduced to 

 protoxide. This red shale is of great extent along the railroad, and presents a 

 thickness of from one to five hundred feet, yet nowhere has a fossil been found 

 in it, or a pebble, or anything extraneous, excepting a few thin layers of sandstone. 

 The main line of the N. Y. C. & H. R. R. R. runs on the Salina formation 107 

 miles, from Canastota to Brighton, and nearly all of this distance on this lower 

 or red shale portion. 



2. The second deposit is the lower gypseous shales, the lower part of it 

 alternating with the red shale, which ceases with this mass . This second deposit 

 consists of shales and calcareous slates of a light green and drab color, with 

 alternations of different colored masses, red, green, bluish and yellow, with a 

 little whitish and greenish sandstone, different colors predominating in different 

 places. In this deposit gypsum occurs in fibrous masses, either reddish or of a 

 salmon color, which colors are peculiar to this deposit. The quantity of gypsum 

 in this second deposit is comparatively small, and it is unimportant in an 

 economical point of view. 



Both the second and third deposits are permeable to water, which cannot be 

 obtained in any of the hills composed of them unless the wells are sunk to the 

 level of the water-courses, a fact which explains the absence of all brine-springs 

 above the level of the country. 



