No. 275. J 
SOI 
The ascent to the south continues for more than half a mile, at which 
point it has attained an elevation of sixty or seventy feet above the 
lake; here the rock becomes nearly horizontal, and so continues for 
nearly a mile, when it again dips to the south, and disappears for the 
last time beneath the lake a short distance south of GofF's point, and 
four miles from its first appearance. The shale, both above and be- 
low pursue the same undulations, proving that this appearance does not 
arise from the limestone having been deposited in an uneven bed in the 
shale. From this rock appearing at so great an elevation above the 
lake at two distant points, it* might, unless carefully observed in its 
southern ascent, be mistaken for two beds, occurring several hundred 
feet apart; and it is only from investigations along the lake shore, that 
we are able to point out the precise cause and manner of its recurrence 
at a point so far south of its outcrop. 
Undulations of the strata are not confined to the extent here men- 
tioned, and we shall have occasion to allude to the same phenomenon 
in rocks farther south; though nowhere so well exhibited as in the case 
just described. A corresponding undulation is seen in the Tully lime- 
stone, on the eastern side of the county, also on the eastern shore of 
Cayuga, and on the western shore of Seneca lake, the amount being 
about the same in each place. The points of final disappearance of the 
rock beneath the water on either side of the same lake are nearly oppo- 
site each other, or in the same line of latitude. This limestone gene- 
rally contains few fossils; in some localities, Calymene, Cryphseus, and 
Atrypa aflfinis are found in considerable numbers, and may be considered 
the characteristic fossils of the rock. The transported masses of the 
same rock which have been found many miles south, all contain the 
same fossils, and thus enable us to refer the loose masses to their ori- 
ginal place. 
The erosive action of the lake waters has removed the shale below 
the limestone in many places, causing it to fall into the lake, where 
huge masses are seen to line and protect the shore for considerable dis- 
tances. In Seneca county these masses are raised from the water and 
carried by boats to the head of the lake, and up the Chemung canal, 
where they are burned for lime. 
Upper Black Shale. Reposing upon the Tully limestone we have a 
thickness of 150 feet of shale, exhibiting throughout a uniform black 
colour, and slaty structure. It differs from the black shale below in be- 
ing more brittle, the surfaces of laminas grained or rough, and contain- 
