Rich.'jioiid Group of Cincinnati Anticline. — Focrstc. 355 
at other localities in the immediate vicinity of Salt river, but 
farther south, in Nelson and ^Marion counties, it seems to be 
absent. On the eastern side of the Cincinnati uplift, the, Dal- 
nmnella jugosa zone is fully represented at Concord, in Ken- 
tucky. It disappears at some point north of Owingsville. The 
upper part of the Lower Richmond has been detected at Spen- 
cer,* and it unquestionably extends farther southward. 
The Middle Richmond also diminishes in thickness south- 
ward. West of the Cincinnati uplift the Middle Richmond has 
been recognized as a distinct formation as far south as the 
mouth of Bull creek in southern Indiana. The fossils belong- 
ing to this horizon, however may be traced much farther south- 
ward. Middle Richmond fossils occur at Bardstown in Xel- 
son county, and at other localities in Nelson and ^Marion coun- 
ties. It is believed that the Middle Richmond has a greater 
southward extension in central Kentucky than the Low'er Rich- 
mond. East of the Cincinnati uplift the Middle Richmond is 
well exposed near Concord, Kentucky. In central Kentucky 
the corresponding horizon seems to consist of argillacerus, 
nearly unfossiliferous rock, and it may apparently be traced as 
far south as Shelby City, four miles south of Danville. 
The Upper Richmond also diminishes considerably in thick- 
ness southward, but its thickness in Nelson and Marion coun- 
ties is sufficiently constant to suggest an extension of this 
formation into southern Kentucky. It is probable that the 
Richmond exposures along Fishing creek, west of Somerset, 
and along the Cumberland river, east of the Cincinnati uplift, 
belong to this horizon. t Hehertella sinnata, ByssoncJiia radi- 
ata^ Ptcrinca dcuiissa, and Streptelasuia rusticmn may occur in 
any part of the Richmond, but the forms of Platystrophia along 
Fishing creek resemble more the small variety with a hinge- 
line scarcely exceeding the width of the shell, occurring in the 
Upper Richmond, than any form commonly found in the ?^ fid- 
dle Richmond. $ 
If these conclusions are correct, the IMiddle Richmond ex- 
tended farther south, in central Kentucky, than the Lower 
Richmond, while the Upper Richmond probably reached nor- 
• "The Cincinnati anticline in Southern KentuckT." Americ.\n Geologist, 
1902, vol. XXX, p. 368. 
t 7Wcf., p. 304. 
X "The Morphogenesis of Platystrophia," B. R. Cu.mings, p 25. 
