438 
The Ohio Naturalist. 
[Vol. XII, No. 3, 
Interval with Leplaena richmondensis rather common in the 
upper part, the lowest specimens occurring near the home 
of J. D. Stansbury 10 ft. 
Strongly cross bedded, rather coarse grained limestone layers, 
forming crescentic sweeps of strongly inclined limsetone 
laminae, striking in a general way North 40° West. The 
concave sides of these crescentic curves face the southwest. 
The length of the curves averages about 20 feet. The total 
thickness of this crossbedded section is not known; it can 
not be less than 6 feet and may equal 12 ft. 
The base of the strongly cross-bedded section is directly east of 
the most northern farm house seen on the western side of 
the creek. 
The most striking features of this section, southwest of Mount 
Washington, are: The presence of Leptaena richmondensis 
throughout a vertical range of 24 feet, with Rhynchotrema dentata 
near the middle of this range. The presence of Platystrophia 
ponder osa for a distance of 10 feet above the Leptaena horizon. 
This strongly cross bedded limestone is regarded as equivalent to 
the lower Amheim elsewhere. It suggests the presence of shallow 
waters with strong currents and in this respect is in rather strong 
contrast with the exposures so far described. Possibly the thick- 
ness of the strata containing Leptaena, and the thickness of the 
underlying cross bedded limestone section have been greatly 
exaggerated, in attempting to estimate their thickness along 
the creek. 
About two and a half miles southeast of Mount Washington, 
Leptaena richmondensis has a vertical range of 14 feet. Platys- 
trophia cypha-conradi is common. Dinorthis carleyi occurs at the 
base. Platystrophia ponderosa occupies a section about 4 feet 
thick, at a distance 10 feet above the Leptaena horizon. Cross 
bedded limestones occur at the base of the Arnheim section, but 
some of the layers near the top also are coarse grained. 
The greatest thickness of coarsed grained, cross bedded lime- 
stone at the base of the Arnheim section is seen about a mile 
northwest of High Grove, in the southwestern corner of Spencer 
county. Here it is 12 feet thick, and is immediately overlaid by 
strata containing Leptaena richmondensis and Rhynchotrema 
dentata. The vertical range of Leptaena has not been established 
here. 
About a mile southeast of Smithville, along the pike to Bards- 
town, coarse grained limestone, 5 feet thick, occurs below layers 
containing Leptaena richmondensis and Dinorthis carleyi. Loose 
specimens of Rhynchotrema dentata also are found. The exact 
succession has not been established beyond doubt. 
About a mile west of Smithville, on the north side of Salt river, 
the coarse grained limestone in the Arnheim section is about 
three and a half feet thick. Platystrophia ponderosa occurs at 
a higher level. 
