38 Bulletin of Laboratories of Denison University [Voi. xi. 
low the bone-bed only. Here are found three common species 
of Favosites, two of ZapliirntiSy two of Atrypa, three of StropJi- 
eodonta and one of Paraeyelas. Moreover L. nianni and I^eior. 
limitains are absent here. (See pp. 33-35.) This fauna mani- 
festly more closely resembles that below the bone-bed than does 
that at Delaware. However, it retains T. sealai'iformis and 5 . 
ziezae in great numbers and these would be sufficient to place 
the fauna above the bone-bed. 
Farther north yet the distinction becomes still less marked. 
At Sandusky are found Su omatopora, CyatJiophylhtin Jialli, two 
species of Cystiphyllurn, one of Zaplirentis, two of Atrypa, four 
of StropJieodonta, one of Paraeyelas, one of Callonema and two 
forms of PJiacops. Moreover S. ziezae has not been found for 
certain at this place. However, 7 . sealariformis occurs, and is 
re-enforced by A. spiriferoides. This fauna resembles more 
closely that below the bone-bed. 
The following shows the number of each class found at the 
three localities : 
This shows that a greater number of species is found as 
one goes north. How'ever, the Delaware formation is as fossil- 
iferous as that at the other two cities named though the number 
of species is smaller. 
The following species are found above the bone-bed and 
are not found below : Lingula manni, Chonetes yandellanus, 
Leiorhynchus limitaris., Athyris spiriferoides., Aviculopecten 
parilis, Grammysia bisulcata, Gyroceras ohioense, Tentaculites 
sealariformis. 
Of these eight forms four have been found, one each, in 
one locality only, two in two localities, and four in four locali- 
ties. (Pis. VI-VIII.) 
