Strophomena and Other Fossils 
27 
and Cleiocrinus, occur in the Curds ville bed. Hehertella hella- 
rugosa is absent at this horizon. I have never found any species 
of Strophomena at this horizon, but Mr. E. O. Ulrich listed Stro- 
phomena filitexta (^^Correlation of the Lower Silurian/^ Am. Geol.^ 
vol. i, p. 108, 1888), a species now included under Strophomena 
incurvata, from the Curdsville. If the Curdsville member finds 
any approximate equivalent in the Ordovician section along the 
northern part of Lake Huron, it must be in the upper part of the 
Black Eiver section, as exposed on Goat Island. There are suffi- 
cient differences in the faunas, however, to make exact equiva- 
lency uncertain. 
The most typical specimens of Strophomena incurvata in central 
Kentucky are found in the Tyrone member. At High Bridge, 
between 24 and 29 feet below the clay at the top of this member, 
there is a richly fossiliferous horizon at which Strophomena 
incurvata is abundant. Here it is associated with Rafinesquina 
minnesotensis, and small specimens referred to Orthis tricenaria. 
I have never found Dalmanella subaequata, Dinorthis deflecta, or 
Hehertella hellarugosa at this horizon, although Mr. Ulrich lists 
the first two species from the richly fossiliferous horizon here under 
consideration, and the last species from the upper, cherty part 
of the Tyrone. The Oregon member contains very few fossils; 
no species of Strophomena has been found. 
Specimens of Strophomena closely resembling Strophomena 
incurvata occur at several horizons in the Camp Nelson member 
of the Stones Eiver group; the only ones recorded were from 35 
and 95 feet below the top of this member. The lower part of 
this division, as exposed near Camp Nelson, Kentucky, has not 
been studied. At High Bridge, Rafinesquina minnesotensis, 
Orthis tricenaria, Hehertella hellarugosa, and Rhynchotrema inae- 
quivalve have been collected between 130 and 140 feet below the 
top of this division. Dinorthis defiecta and Dalmanella suhae- 
quata are known from 120 feet below the top. Judging from the 
published lists of fossils from the equivalent strata in southern 
Tennessee Columbia folio,^^ U. S. Geol. Surv., Hayes and 
Ulrich, 1903), the Camp Nelson member corresponds to the Leb- 
anon and Eidley members of the Stones Eiver group. Appar- 
ently most of the exposed part of the Camp Nelson member, at 
High Bridge, belongs to the Lebanon member. In Tennessee, 
