90 The American Geologist. August, i904. 
lynx and '■'Coelocleiiia ozvcni to the top of the Lorraine is yy 
feet, but the lower part of this interval does not contain diag- 
nostic fossils. 
At Cincinnati, the Mount Hope-Fairmount section has a 
total thickness of about 130 feet. In southern Indiana, be- 
tween Vevay and Brooksburg, this thickness averages be- 
tween 90 and 95 feet. The occurrence of Sfrophomciia plan- 
iconvexa, Hebertella siiiiiata, PlcctortJiis plicatclla, and of the 
small Mount Hope form of Platystrophia, species first seen at 
the base of the Fairmont bed in Ohio, near the base of the 
Lorraine section in southern Indiana suggests that the consi'd- 
erable diminution of the Mount Hope-Fairmount section 
southward is due chiefly to the thinning of the Mount Hope 
bed. 
At Cincinnati, the thickness of the Corryville bed is esti- 
mated at about 60 feet. At ^Madison, in Indiana, the base of 
the Mount Auburn layers containing PlatystropJila lyiix and 
Cocloclcma oivcni is 80 feet below the top of the Lorraine. The 
top of the Bellevue bed is between 130 and 134 feet below the 
top of the Lorraine. Bythopora gracilis and Callopora rainosa 
characterize the section up to 90 feet below the top of the 
Lorraine. The strata intervening between this level and the 
base of the upper Platystrophia lynx layers, known to be of 
Mount Auburn age, consist of nodular limestone and clay of 
unknown age. The thickness of the Corryville bed at Madison, 
therefore, can not exceed 54 feet, and possibly may not exceed 
44 feet. At Lebanon, the thickness of the Alount Auburn bed 
is estimated by INlr. J. M. Nickles at about 20 feet. At ^Nladi- 
son, only three feet can be definitely assigned to this bed, al- 
though the imderlying, doubtful section, 10 feet thick, also may 
belong to this bed. 
At Fredericktown, Kentucky, seventy miles south of ^ladi- 
son, the top of the great Platystrophia lynx bed, presumably of 
Bellevue age, is about 90 feet below the top of the Lorraine. 
Strophoincna planiconvcxa occurs 107 feet below the top of 
the Platystrophia lynx bed. This indicates the continued thin- 
*A11 bryozcans mentioned in this paper were identified b.v Mr. R. S. Bass- 
ler. Tliese identifications in addition to many otliers form tlie basis of the 
stratigraphioal worlv liere described. The writer desires to express his great 
oblisations for the favors received. Although much more abundant collec- 
tions of fossils are necessary to determine the exact limits of the various 
subdivisions in Indiana, the pi'esent paper is offered as a contribution pre- 
liminaj-y to such more detailed study. 
