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, Eurypterus remipes, Spirifer plicatus, and Leperditia alta. 



The rock composing Rattlesnake 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 



