28 Aug. F. Focrste 



■of Fisherville: and immediately south of Clay Village, at the 

 northern foot of Jeptha Knob. At Jeptha Knob, this variety of 

 RJiynchotreum occurs 945 feet above sea level, associated with 

 Platystrophia ponderosa. At 985 feet Dalmanella inultisecta is 

 ■common, indicating a fault equivalent to the entire thickness of the 

 Alaysville formation. At Madison, Indiana, a single specimen of 

 Rhynchotrenia dentafa-arnheimensis was found years ago by Mr. 

 John Hammell, at the xA.rnheim horizon. So far, no specimens have 

 been found in the Arnheim north of Madison, Indiana, or Ander- 

 sonville, Ohio. Southward, in Tennessee, however, they occur at 

 Goodlettsville, Newsom, and Clifton. 



The horizon for Rhynchotrenia dentata-arnhcimensis is near 

 the middle of the Arnheim bed, associated with Dinorthis carleyi, 

 and above the Lcpfaena richniondcnsis-prcciirsor horizon. At Madi- 

 son, Indiana, Platystrophia ponderosa occurs near the lower end 

 of the first railroad cut. Leptaena richmondensis-prectirsor is 

 found 7.5 feet farther up. Dinorthis carleyi makes its appearance 

 4 feet above the latter, and is rather common for a distance of a 

 foot and a half. The interval between the Dinorthis carleyi horizon 

 and the top of the culvert at the upper end of the cut is 30 feet. 

 At Arnheim, the lowest specimens of Leptaena occur 5 feet above 

 the Platystrophia ponderosa layer. The vertical range of the Lep- 

 taena is three feet nine inches. Rhynchotrenia occurs in the upper 

 six inches of the Leptaena horizon, and is overlaid by the Dinorthis 

 ■carleyi layer. 



The strata containing' Lelyfacna richmondensis-precursor , 

 Rhynchotrema dentata-arnheinicnsis. and Dinorthis carleyi inaugu- 

 rate a new fauna. They are the first representatives of the Rich- 

 mond fauna among the brachiopods. From this horizon upward, 

 the rocks usually are much more richly fossiliferous than those 

 beneath, especially those beneath the Platystrophia ponderosa hori- 

 zon. This is true especially southward and on the eastern side of 

 the Cincinnati geanticline, in Mason, Fleming, and Bath counties. 

 At Maysville, the upper, fossiliferous division of the Arnheim bed 

 is 26 feet thick, the comparatively unfossiliferous argillaceous lime- 

 stone layers beneath having a thickness of 16 feet. The latter 

 represent an ingression of muddy sediments, similar to the later 

 ingressions resulting in the formation of the Saluda and Elkhorn 

 beds. For these, comparatively unfossiliferous argillaceous lime- 

 stones, forming the lower half of the Arnheim section, as formerly 



