22 



[Assembly 



skany sandstone, and tLe otlier from the limestone of the LoTsr Helder- 

 berg group. 



ITS 2 



The figures 1 and 2 are illustrations of well-marked species from the Oriskany 

 sandstone. 



Fig. 3 is of another species from the same rock^ showing the same general charac- 

 ter of the columella. 



Under this genus I have described the Strophostylas elegans, S. globosus> 

 S. ohtusus^ S. depressus, S. fitchi and S- rotundatus, from the rocks of the 

 Lower Helderberg group ; and S. transversi's, S. matheri, S. andrew si a.nd 

 S. erpansas from the Oriskany .Sandstone. 



