202 GEOLOGY OF OHIO. 



of this formation to be found in the State. The group of islands which 

 cluster around Put-in-Bay are separated by narrow channels, and seem 

 originally to have formed a single mass. The limestone of which they 

 are composed exhibits evidences of having been lifted and shattered, 

 and the relief of these masses is, probably, in part, due to upheaval. 

 As has been before stated, these islands lie in the track of the Cincinnati 

 arch, and it would seem that there had been some disturbance long sub- 

 sequent to the original upheaval. The evidences of this disturbance are 

 seen in the irregularity of the bedding of the limestone, and in belts 

 along which it appears to have been completely shattered, and subse- 

 quently re-cemented ; as in these belts large fragments are not unfre- 

 quently seen standing at right angles to their former position, which is 

 distinctly marked by their stratification. It would also seem that along 

 these lines of fracture several thermal springs once arose to the surface, 

 for we here find the interstices of the brecciated rock not unfrequently 

 filled with masses of calc spar, sulphate of baryta, sulphate of strontia, 

 and native sulphur. 



We nowhere get upon the island a complete section of the Waterlime 

 group, as its upper portion and junction with the Oriskany and Cornifer- 

 ous are buried in the channel between Kelly's Island and Put-in-Bay. 

 At the southern point of Put-in-Bay Island, however, we have the base 

 of the Waterlime and an exposure of the upper part of the Salina. The 

 section at this point is as follows : 



1. Gray brecciated limestone, massive, and without fossils 30 feet. 



2. Oream-colored, thin-bedded limestone 3 to 7 " 



3. Gray brecciated limestone, similar to r\o. 1, containing im- 



mense numbers of Leperditia alta 8 " 



4. Thin-bedded, dove-colored, or gray, laminated, earthy lime- 



stone, with fossils ; used for waterlime 12 " 



5. Blue, earthy, massive limestone, weathering chocolate, with- 



out fossils, at lake level 10 " 



In the foregoing section the last number belongs to the Salina group, 

 and its surface marks the junction between the Salina and the Waterlime. 



Just off South Point the anchors of vessels frequently drag up masses 

 of gypsum, which shows that the Lake bottom is composed of that mate- 

 rial. On the Peninsula, eight miles distant, the gypsum comes to the 

 surface, and is extensively worked. Here it is overlain by blue, earthy 

 limestone, similar in character to the limestone exposed on Put-in-Bay 

 Island. 



At the northern end of the island last mentioned, the dip being in 

 this direction, higher beds of the Waterlime group are exposed. These 

 are similar in character to those of South Point, viz., massive and brec- 



