438 The Ohio Naturalist. [Vol. XII, No. 3, 



Interval with Leptaena 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 

 ponderosa 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 sovitheast 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 Amheim 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 Amheim 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 Smithvillc, 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 Smith\'ille, on the north side of vSalt river, 

 the coarse grained limestone in the Arnheim section is about 

 three and a half feet thick. Platystrophia ponderosa occurs at 

 a higher level. 



