250 The Ohio Journal of Science [Vol. XVII, No. 7, 



The fold is higher and narrower, and therefore, more convex, 

 the angle made by the sides averaging 20 degrees or less. The 

 specimen iUustrated by Figure 5c in the Paleontology of New 

 York is represented by Figure 8 on Plate XI of the present 

 publication. 



At Harrods Creek, about five miles northeast of Louisville, 

 Kentucky, a specimen of Dictyonella was found in the Upper 

 Osgood clay, which here forms a layer about three and a half 

 feet thick, 20 feet below the level of the traction bridge, about 

 200 yards up stream from the bridge. Here it is associated 

 with Cyathophyllum calyculum, Eucalyptocrinns, Hallopora ele- 

 ganluJa, Orthis flabellites, RhipidomeUa hybrida, Leptcena rhom- 

 boidalis, A try pa reticularis, and Diaphorostoma ?nagarensis. 

 The Upper Osgood clay is underlaid by the Osgood limestone, 

 six feet thick, with one of Miller's species of "Holocystites'' 

 {Trematocystis ?) at the base. This is underlaid by the Lower 

 Osgood clay, consisting, in descending order, of massive, indu- 

 rated clay rock, 9 feet thick, spalling where exposed to weather- 

 ing; chiefly purplish clay, 3 feet thick; and more indurated clay 

 rock, 8.5 feet thick. In the underlying Brassfield limestone 

 Orthis flabellites is associated with Rhinopora verrucosa. 



The Dictyonella found in the Upper Osgood clay is scarcely 

 distinguishable from the Dictyonella reticulata occurring in the 

 Waldron shale. It possesses the same low median fold, not 

 strongly defined laterally, and becoming more or less obsolete 

 toward the beak. The surface markings are closely similar, 

 and, although appearing more circular on some parts of the 

 sheU, are equally quadratic on others. (Figs. 4 A, B, on plate X.) 



It is interesting to note that this Osgood form of Dictyonella 

 finds its nearest relative in the Waldron species, Dictyonella 

 reticulata, rather than in the Rochester form, Dictyonella 

 cor alii f era. 



Camarotoechia roadsi, sp. nov. Plate XII, Figs. 6 A-E. 



General outline rotund subtriangular, especially when viewed from 

 the side of the pedicel valve. Pedicel valve only moderately convex in 

 appearance since the antero-lateral parts have almost the same eleva- 

 tion as the umbonal parts of the valve. Brachial valve strongly convex, 

 especially anteriorly, along the median fold, where the median parts are 

 conspicuously elevated above the lateral parts of the valve. Median 

 fold with four plications, the lateral ones narrower and at a some\yhat 

 lower elevation. Lateral plications, on each side, five or six, sometimes 



