446 The Ohio Naturalist [Vol. XII, No. 3, 



about three-quarters of a mile southwest of Rush Branch postoffice, 

 Leptaena richmondensis and Rhynchotrcma dentata occur at the 

 base of several feet of argillaceous limestone containing Platys- 

 trophia ponder osa. 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 ponder osa. 



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 cla^^ nodules 1 in. 



Greenish clay shale 5 in. 



Argillaceous limestone rublsle interbedded with irregular indu- 

 rated fossiliferous clay masses and consideraljle softer clay, 

 containing Leptaena richmondensis, Platystrophia cypha- 

 conradi, Anomalodonta gigayitea, Byssonychia radiata, Heher- 

 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 8 in. 



Argillaceous rock, splitting into irregular thin layers and break- 

 ing up into small fragments owing to vertical cracks 6 ft. 



Interval, covered 4 ft. 6 in. 



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 occasiorial 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. 



Rhynchotrcma 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 

 jngosa var. and an occasional specimen of Platystrophia ponderosa, 



