238 Onto StTaTE ACADEMY OF SCIENCE 
been reached by the rising water, the whole of Cedar Point may 
share the fate of Peninsula Point at no distant date unless 
jetties, piers, cribwork, etc., suffice to save it. 
The bay with the connected marshes is probably twenty 
per cent larger now than in 1820. So far as the enlargement is 
due to erosion it should proceed more rapidly the wider the bay 
becomes, for the waves attain greater force. The effect of the 
waves, however, is diminished by the bay bridge, by jetties at 
the entrance to the bay, by docks and by stones put on the shore 
purposely to protect the land. The enlargement of the bay due 
to the subsidence of the land may be partly prevented by dikes 
and may be effected to some extent by changes at Niagara Falls 
produced by human agency. We may reasonably expect, how- 
ever, that the bay will continue to spread over the adjacent low- 
land much as it has been doing for centuries past. 
The rise of the water due to tilting of the land, 2.14 feet in 
a century, is about the same as the change of lake level that some- 
times occurs within a year in consequence of variations in the 
rainfall and is considerably less than that produced in Sandusky 
Bay by a single northeast gale. It is, however, cumulative. The 
present generation is likely to see the water higher than it was in 
1858 and in northeast gales the lower parts of Sandusky sub- 
merged, but at the present rate of subsidence the bay at ordinary 
stages of the water will not extend up Columbus Avenue as far 
as Market Street for about eight hundred years. Port Clinton 
is not so fortunately situated. Northeast gales will cause much 
trouble there as soon as there comes a period of several years 
when the rainfall is considerably above normal, and before the 
middle of the next century the water at such times will go quite 
across the peninsula from Port Clinton to Sandusky Bay. After 
two or two and a half centuries the water will cover this part of 
the peninsula for months at a time and after three centuries will 
do so at ordinary stages. Marblehead will then be an island and 
Sandusky Bay will show no resemblance to its present form. 
