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 limestone 
containing Platystrophia ponder osa. 
In this area including the eastern part of Bullitt 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 <?f 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 
dentata, and the latter by layers containing Platystrophia pon- 
der osa. 
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 from 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 county, 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 about 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 
