THE ISLANDS. 203 
ciated layers, intersected by thin sheets of laminated limestone. These 
latter, at Peach Point, have furnished large numbers of fossils which 
serve to identify accurately the formation with the Waterlime of New 
York. These are, Hurypterus remipes, Spirifer plicatus, and Leperditia alta. 
The rock composing Ruttlesnake Island, Middle Bass, Sugar Island, 
etc., is precisely similar to that which forms the mass of Put-in-Bay Is- 
land; and, therefore, the geology of those islands requires no detailed 
description. I should mention, however, that on North Bass there were 
obtained from a well sunk for water some unusually fine masses of 
crystallized celestine; and on Rattlesnake Island I procured a large 
quantity of fluor spar in brown crystals. Green Island also deserves 
special notice, as it has furnished nearly all the fine specimens of crys- 
tallized celestine which have been obtained in this country—much finer, 
indeed, than are known to exist any where else in the world. The 
celestine here occurs in masses of many tons weight, filling pockets and 
fissures in the limestone. This island is a light-house station, and be- 
longs to the United States Government. If possessed by private parties, 
it is quite possible that the strontian might be profitably worked, to 
meet the demand for the nitrate of strontia, which forms the red fire of 
theaters and of pyrotechnical displays. The splendid crystals of celes- 
tine obtained from Green or Strontian Island are found studding the 
walls of cavities. They are sometimes met with as large as one’s hand, 
and almost perfectly transparent throughout. 
The cavernous character of the Waterlime group has been referred to 
in another part of this report. Of this we have striking examples in 
the group of islands now under consideration, and in the neighboring 
peninsula and highlands. The surface of Put-in-Bay Island shows a 
great number of depressions, or “sink-holes,” which are nothing else 
than caves of which the rooofs have fallen in; and it seems probable 
that nearly the whole mass of the island is honey-combed by subterra- 
nean galleries. Several of these have been entered, and two of them 
constitute the chief curiosities of the island for the numerous visitors 
who make this a place of summer resort. One of these, ‘‘ Perry’s Cave,” 
as it is called, has special geological interest. It is plainly a subter- 
ranean channel of drainage, like most caves in these limestone rocks, 
which are generally filled with the water of the Lake. The water which 
stands in this cave is known to have the same level as that of the lake 
surface without, and it rises and falls with all the temporary oscillations 
of level which the Lake undergoes. The lower portion of the cave is now 
completely submerged, and how deeply it sinks, or whither it leads, is 
not known. The part which is above the water-line was formerly hung 
