PLATE 7. 
or obsolete : and the structure of the siphuiiculus and 
chambers, very seldom apparent. A less globular variety of 
this shell is frequent in the light coloured limestone, near 
Buxton and Castleton. 
Fig. 3. Shows the specimen placed on one side. 
The back of the outward whirl. 
5. The end of the outward whirl, broken off at one of 
the partitions, a. the siphunculus. b. b. the lateral cavities. 
The substance of this specimen a greyish black Swinestone. 
