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



Stromatocerium occurs also four and a half miles south of Paint 

 Lick, or 15 miles southwest of Richmond. Here it occurs about 

 S feet above the base of the Orcgonia division. The richlv fos- 

 siliferous part, containing PJatystrophia ponderosa and Lcptaena 

 richmondensis, forms the lower five and a half feet of this division. 

 The top of the lower Arnheim consists of fossiliferous dove colored 

 limestone, 5 feet thick, representing the fine grained limestone 

 layers containing gasteropods, as seen at Cobb Ferry, College Hill, 

 and at the mouth of Red river. Below the dove colored limestone, 

 the characteristic shale bed of the lower Arnheim, 13 feet thick, 

 is found. 



The unfossiliferous shaly layers, characteristic of the lower or 

 Sunset division of the Arnheim, may be traced with confidence as 

 far west as Stanford. At three localities along the southwestern 

 border of Garrard county, the thickness of the shaly layers varies 

 from 16 to 17 feet, and that of the overlying dove colored lime- 

 stones, at the top of the lower Arnheim, from four to five and a 

 half feet. These localities are: half a mile east of the northern end 

 of Preachersville ; three miles southeast of Lancaster, a few hun- 

 dred yards west of the pike, along Gilbert creek; and two and a 

 half miles southwest of Lancaster, west of the pike to Stanford. 

 Farther westward, apparently, the shaly part of the lower Arnheim 

 thins rapidly. Two miles northeast of Stanford, and also two and 

 three-quarter miles north of Stanford, along the road to Lancaster, 

 the thickness of the shaly section is reduced to 7 feet, the overlying 

 dove-colored limestone, at the top of the lower Arnheim, measur- 

 ing three and five feet respectively. 



The territory between Stanford and the mouth of Red river 

 may be regarded as representing a distinct phase of the Arnheim 

 sedimentation. Within this territory the lower Arnheim is 

 characterized by an unfos.'-'iliferous shaly rock overlaid by a thinner 

 section of dove colored limestones. The basal part of the upper- 

 Arnheim division contains Lcptaena richmondensis and RJiyncho- 

 trema denlata, the latter at a slightly higher elevation whenever a 

 difference in elevation is noted. The overlying part of the upper 

 Arnheim section usually is richly fossiliferous, and contains among 

 other fossils rather numerous specimens of Platystrophia ponderosa. 

 At the top of the Arnheim section there is a layer of light colored 

 clay, one or two feet thick, frequently containing numerous 

 specimens of bryozoans. This clay layer has been assumed to 

 form the base of the Waynesville bed, but it may be necessary to 

 revise this classification when the fauna is better known. It is 

 probable that most of these features ma\' be detected as far north 

 as Howards Mill, in the eastern part of Alontgomery county. 



The territory from Montgomer}' county to Mason county, 

 already described, includes another phase of Arnheim sedimenta- 

 tion. Here the lower Arnheim consists of a rather uniform 



