552 GEOLOGY OF OHIO. 



A form with the spire much less elevated than Usually, with the 

 transverse striae well developed though less sharp, and with the revolving 

 striae indistinct or obsolete on the last whorls, except towards the under 

 surface of the shell, represents another extreme of this species, comparable 

 with the form last described. It is not improbable that the earlier whorls 

 also showed the revolving striae more distinctly. This form occurs at 

 Soldiers' Home (Plate 26, Figure 15). 



Finally a form occurs which differs from the ordinary types enough 

 to form at least a distinct variety. In it the transverse striae are very 

 fine and close, much more so than in ordinary forms. Of the revolving 

 striae only the stronger ones remain. These are much more distant from 

 each other, and are strongly raised, the intermediate parts of the shell 

 being strongly concave in cross section. It is these distant coarse revolv- 

 . ing ridges which gave the name varicosum to the variety. This feature 

 can be seen already at the end of the second whorl, which indicates that 

 it is a variation of a much more distinct character than the others so far 

 described. The altitude of the spire is quite normal. This variety 

 occurs at Soldiers' Home, and Todd's Fork, being not uncommon at the 

 latter locality. (Plate 37A, Fig. 9.) 



Cyclora alt a, Foerste. 



(Plate 26, Figs. 17a, b.) 



This species looks very much like a very small Holopea. The speci- 

 mens seem to occur almost invariably in the form of smooth casts. In 

 one single specimen it was thought that minute transverse striae could be 

 detected under a lense. It is very common in certain parts of the "Bea- 

 vertown marl" at Huffman's Quarry, and occurs also in the corresponding 

 layer at Geo. Young's Quarry. At the latter quarry it occurs also in the 

 upper shaly courses of the Clinton. . 



Straparollus (cf. Oriostoma) incarinatum, sp. nov. 



(Plate 37a, Fig. 7a,b.) 



The transverse striae show no trace of sinuous flecture anywhere, 

 corresponding to the obtuse sinus of Straparollus. Any possible affini- 

 ties of this species with Oriostoma can not safely be determined as long 

 as no characteristic operculum has been found. Some species of Stra- 

 parollus have a sinus so faint that it would be but a small step to this 

 specimen, which shows none at all. The spire is very depressed, rising 

 but four-fifths of a millimeter above the surface of the last whorl near 

 the aperture. The total height of the shell is 4 mm. The greatest width 

 is 7 mm. The mouth is round, but situated oblique to the vertical diam- 

 eter. The umbilicus is wide, permitting a view of all the whorls from 



