244 The American Geologist. October, 1905 
NOTES ON THE DISTRIBUTION OF BRACHIOPODA IN THE 
ARNHEIM AND WAYNESVILLE BEDS. 
By Aug. F. Fokhstk, Dayton, Ohio. 
In the first volume of the Geology of Ohio, published 
in [873, on page 397, Prof. Orton states that the lowest 
horizon at which Leptaena rhomboidalis {Strophomena 
tenuistr'iatd) is found is at the very summit of the Cincin- 
nati hills, or about 455 feet above low water. The geo- 
l( igical horizon at which the Leptaena occurs at Cincinnati 
is fixed by the statement, on page 394, that at a bight of 425 
feet above low water a belt of rock, two to ten feet in thick- 
ness, occurs which is almost entirely composed of the ventri- 
cose full-grown shells of Platystrophia lynx [Or this bifor- 
ata.) This "Lynx horizon was considered as forming virtu- 
ally the summit of the Cincinnati section, notwithstanding 
the occurrence of Leptaena rhomboidalis at a higher hori- 
zon. The reason is given on page 370, where it is stated 
that the greatest elevation above low water in the imme- 
diate vicinity of Cincinnati is given by the city engineer as 
465 feet. Subtracting 15 feet for the drift covering at the 
surface we can certainly find 450 feet of bedded rock at Cin- 
cinnati, almost every foot of which lies open to study with- 
in the city limits. The only stratum, however, that admits 
of easy identification, lies at an elevation of 425 feet above 
the river, and this accordingly is assumed as the upper limit 
of the division to which Prof. Orton gave the name Cin- 
cinnati beds proper. 
The Platystrophia lynx horizon at Cincinnati forms the 
AN mnt Auburn bed of Nickles (The Geology of Cincinnati, 
Journal. Cincinnati Soc. Nat. Hist, 1903). If its thickness 
be estimated at 20 feet, it is evident that the specimens of 
Leptaena must have occurred at least 10 feet above the base 
of the Arnheim or Warren bed. This estimate is probably 
too low, but the former presence of the lower part of the 
Arnheim bed at Cincinnati is certain. 
Laptaena rhomboidalis is widely distributed in the Arn- 
heim bed. In Ohio and Indiana it occurs near the middle 
of the bed, making its first appearance a short distance be- 
low the Dinorthis retrorsa horizon and continuing to a little 
.above this horizon. It occurs at this horizon along Reser- 
