Jan., 1912.] The Arnheim Formation. 439 



Near the home of Asa Lutes, southwest of the Grinwell ford, 

 Leptaena is present within two feet above a cross bedded Hmestone 

 containing PlatystropJiia ponderosa. 



In this area inckiding the eastern part of BulHtt county, the 

 southeastern part of Jefferson county, and the adjacent parts of 

 Spencer county, the Arnheim is more variable from exposure to 

 exposure than in any other known area of equal size. This prob- 

 ably is due to shallow water conditions and current action. 



About a mile west of Fisherville, Dinorthis carleyi is overlaid 

 by strata containing Leptaena richmondensis and Rhynchotrema 

 dciitata, and the latter by layers containing PlatystropJiia pon- 

 derosa. 



This is the most northern locality at which Platystrophia 

 ponderosa is known to occur above the Leptaena horizon, on the 

 western side of the Cincinnati geanticline. North of Fisherville, 

 Platystrophia ponderosa is known only froin below the Leptaena 

 horizon. A similar succession is noted on tracing the Arnheim 

 strata on the eastern side of the Cincinnati geanticline northward. 

 As far as the mouth of the Red river and Howards Mill, Platys- 

 trophia ponderosa is found above the Leptaena horizon as well as in 

 the underlying Maysville beds, but toward the Ohio river and 

 northward, this species occurs only below the Leptaena horizon. 



About a mile northeast of Pendleton, in Henry county, Dinor- 

 this carleyi occurs immediately above a section, two feet thick, in 

 which Leptaena richmondensis is common, but the latter species 

 occurs also 6 feet farther up. 



At Scott's Hill, in the eastern part of Trimble cotmty, four 

 miles east of Bedford, Dinorthis carleyi and Leptaena richmondensis 

 occur in the Arnheim, and they occur also at Milton, on the Ohio 

 river, with Dinorthis carleyi about two feet above the Leptaena 

 richmondensis horizon. 



5. Indiana. 



Along the railroad in the northwestern part of Madison, 

 Indiana, Dinorthis carleyi is rather common in a section abotit a 

 foot and a half thick. Leptaena richmondensis occurs about four 

 feet lower, and the horizon for Platystrophia ponderosa is seven 

 and a half feet farther down. 



Platystrophia ponderosa is not known in the Arnheim of Indiana 

 anywhere north of Madison. Leptaena richmondensis is associated 

 with Dinorthis carleyi about a mile southeast of Sparta, or eight 

 miles west of Lawrenceburg ; five miles east of Brookville, on Big 

 Cedar creek; and a mile north of Brownsville or five miles north- 

 west of Liberty. It is a comparatively rare fossil in Franklin and 

 Union counties, however, and it has not been found at any locality 

 between Franklin county and the Ohio river except at Madison. 

 Even Dinorthis carleyi is comparatively rare in the area south of 



