440 
The Ohio Naturalist. 
[Vol.XII, No. 3, 
Franklin county, although this is the only one of the fossils charac- 
teristic of the basal part of the upper or Oregonia division of the 
Arnheim which has a fairly general geographic distribution in the 
area designated. In most of this territory, the Arnheim consists 
of argillaceous limestone, and indurated clay layers interbedded 
with much larger quantities of soft clay. The lower Arnheim 
does not differ lithologically from the upper part. 
The chief characteristic of the Arnheim in Franklin and Union 
counties, in Indiana, is the presence of a variety of Dalmanella 
jugosa in rather large numbers. Northwest of the home of William 
Bauman, two miles southwest of Brookville, Dalmanella has a 
considerable vertical range above the Dinorthis carleyi horizon. 
At New Trenton, Indiana, Dalmanella has a considerable vertical 
range below the Dinorthis carleyi layer; in fact, it occurs even as 
low as the Mount Auburn. North of Brookville, as far as the 
northern boundary of Franklin county, Dalmanella ranges from 
several feet above the Dinorthis carleyi horizon to at least 10 
feet below that level. 
6. Ohio. 
Dalmanella has a considerable vertical range in the Arnheim 
also in the western half of Hamilton and Butler counties, in Ohio. 
Farther eastward, as far as Adams county, on the Ohio river, 
Dalmanella is restricted, in the Arnheim, to a vertical range of only 
a few inches, at or immediately above the Platystrophia ponder osa 
horizon, and distinctly beneath the Leptaena richmondensis and 
Dinorthis carleyi horizons. Wherever, at these more eastern 
localities, Dalmanella has a considerable vertical range, it is known 
to characterize the Waynesville member. The result is that, 
farther eastward, Dalmanella may be used to identify readily the 
Waynesville member, especially the lower part, where other con- 
spicuous characteristic fossils are not common, while in the western 
part of Butler and Hamilton counties, and in Franklin county, 
this species may prove misleading if only a superficial study be 
given to a line of outcrops. 
A most peculiar section, differing in some respects from any 
other known, occurs about a mile north of Collinsville, or eight 
miles northwest of Hamilton, Ohio. The top of the Arnheim 
is not exposed. 
Nodular argillaceous limestone near the top of the Arnheim. . . 2 ft. 
Interval with Byssonychia and Rafinesquina common 11 ft. 6 in. 
■Clay with Dalmanella and with a single loose specimen of 
Dinorthis carleyi which may have come from this horizon. . 3 ft. 6 in. 
Clay and limestone. Topmost layer wave-marked 7 ft. 4 in. 
Dalmanella abundant in clay and thin limestone 6 ft. 8 in. 
Clay interbedded with limestone 6 ft. 9 in. 
Argillaceous rubble limestone 2 ft. 9 in. 
Highest Leptaena richmondensis horizon. 
Interval with Platystrophia ponderosa at various levels 1 ft. 9 in. 
Leptaena richmondensis. 
Interval 1 ft. 8 in. 
Platystrophia ponderosa just above creek level. 
