446 
The Ohio Naturalist. 
[Vol. XII, No. 3, 
about three-quarters of a mile southwest of Rush Branch postoffice, 
Leptaena richmondensis and Rhynchotrema dentala occur at the 
base of several feet of argillaceous limestone containing Platys- 
trophia ponderosa. On the Steele Knob road from Chilton post- 
office to Liberty, about a mile south of South Fork of Rolling 
Fork, near the northwestern edge of Casey county, Leptaena 
richmondensis occurs three feet below strata containing Platys- 
trophia ponderosa. 
Near the northeastern edge of Adair county, about a quarter 
of a mile south of the road from Dunnville to Neatsville, along 
Damron creek, twenty miles south of the localities on the South 
Fork of Rolling Fork, Leptaena richmondensis and Platystrophia 
cypha-conradi occur in the following section: 
Greenish clay shale 7 in. 
Irregular hard clay nodules 1 in. 
Greenish clay shale 5 in. 
Argillaceous limestone rubble interbedded with irregular indu- 
rated fossiliferous clay masses and considerable softer clay, 
containing Leptaena richmondensis, Platystrophia cypha- 
conradi, Anomalodonta gigantea, Byssonychia radiata, ILeber- 
tella occidentalis and other fossils 3 ft. 2 in. 
Spalling clay rock 1 ft. 2 in. 
Shaly material weathering into small fragments 5 in. 
Argillaceous limestone Sin. 
Argillaceous rock, splitting into irregular thin layers and break- 
ing up into small fragments owing to vertical cracks G ft. 
Interval, covered « 4ft. Gin. 
Damron Creek. 
Platystrophia ponderosa is exposed at a lower horizon, farther 
up the creek, in hard, fine grained, bluish limestone, apparently 
corresponding to the dove colored limestones below the Arnheim 
horizon in Lincoln, Garrard, and Madison counties, northward. 
10. Western Tennessee. 
Nearly a hundred miles southwest of Damron creek, nearly 
four miles north of Gallatin along the railroad toward South 
Tunnel, Leptaena richmondensis associated with Platystrophia 
ponderosa occurs at the Arnheim horizon in a section about 12 feet 
thick. In the lower half of this section consisting of argillaceous 
limestone, both species are common. In the upper part, consisting 
of more coarse grained limestone, only occasional specimens of 
Leptaena occur. At the very top of the section, small specimens 
of Dalmanella are found. Platystrophia ponderosa continues 
common for ten feet below the lowest strata at which Leptaena 
occurs. 
Rhynchotrema dentata is common in the Arnheim eight miles 
northeast of Goodletsville, about ten miles west of Gallatin, in 
Tennessee. It occurs in the Arnheim, associated with Dalmanella 
jugosa var. and an occasional specimen of Platystrophia ponderosa, 
