204. GEOLOGY OF OHIO. 
with stalactites, and the floor covered with stalagmites, many of which 
still remain. These, as is well known, are formed by the dripping from 
the roof of water holding lime in solution, and the precipitation of this 
lime both on roof and floor. This precipitation could, of course, only 
take place in air, and would be impossible in a gallery filled with water. 
But during the last summer the interesting discovery has been made by 
Capt. John Brown (who resides on the island, and has given much atten- 
tion to its geology) that the floor of the cave was studded with stalag- 
mites far below the present level of the Lake. This shows very palpably 
(what is, however, taught by the very existence of the cave) that the lake 
level was once much lower than at present, and that all that part of the 
cave which is now under water was once filled with air, through which 
the water dripped from roof to floor, precipitating its lime, as is now 
done in the upper portions of the caver | 
The limestone of which Put-in-Bay and the adjacent islands are form- 
ed, as proved by our numerous analyses, is nearly a typical dolomite— 
that is, it contains more than 40 per cent. of magnesia. This composi- 
tion of the stone has been cited as proof that it was unfit for the manu- 
facture of lime; but, as a matter of fact, the lime which is most esteemed 
in the southern part of Ohio, and in many other portions of the country, 
has nearly the same composition as that obtained from the Put-in-Bay 
Island stone. For example, the lime most esteemed in Cincinnati, de- 
rived from the Niagara group, and obtained at Springfield, Yellow 
Springs, and Cedarville, has almost the composition of the Put-in-Bay 
waterlime, as will be seen by the table of analysis given below. The 
lime preferred above all others in the city of New York is that manufac- 
tured from the Sing Sing marble, which is a typical dolomite, contain- 
ing— 
Warbonmateyor Wives os ees oS UES Raa Ee eee 53.24 
Carbonate OhpMaACNeslait loc icc .oeotes isco seeee eee en eewecssGececuseeetee ctnen Lecmeas 45.89 
SLT CAAT ASAT UTNE Me EN EC TRIAS Dea a aig one SR aes ate ee 87 
100.00 
ANALYSES oF THE Massive Beps or THE WATERLIME Group, Purt-1n-Bay IsLAND, 
MADE BY Pror. EK. W. Roov. 
1 2 a 4 
Garbonatevon lime Heyy t eee ee 49.03 55.40 54.23 63.37 
Carbonate of Magnesia.........sceee 41.64 42.37 44,98 32.57 
Alumina and oxide of iron........... 0.40 0.30 0.56 0.40 
Insoluble residue ...... ..ccccces seseos cee 0.30 0.29 0.74. 0.33 
OSS HO WAI SIMIGTOMM esc cecssncencurwccesiees 1.81 1.15 0.35 0.68 
