TABLE OF CONTENTS. 
Page. 
PREFACE.xiii-xv 
GASTEROPODA, of the Upper Helderberg, Hamilton, Portage and Chemung groups 1-138 
Platyceras : Descriptions of species.1-21 
Platyostoma : Descriptions of species ..21-30 
Strophostylus : Descriptions of species.30-32 
Macrocheilus : Descriptions of species.32-34 
Cyclonema : Descriptions of species.. 34-39 
Loxonema : Descriptions of species.39-49 
Callonema : Descriptions of species ..50-54 
Euomphalus : Descriptions of species.54-63 
Pleurotomaria : Descriptions of species.64-88 
Murchisonia : Descriptions of species.89-93 
Bellerophon, of the Upper Helderberg—Chemung groups .... 94-123 
Species of the Upper Helderberg group ...... 94-99 
Species of the Hamilton group ......... 100-117 
Species of the Chemung group . . . . . . . 117-121 
Distribution of species ..121, 122 
Cyrtolites, subgenus Cyrtonella : Descriptions of species. . . . 123-126 
Porcellia : Description of species ......... 126-128 
Addenda to the GASTEROPODA: Loxonema, PAL^OThocHUs’and Turbo . 129-137 
Note on Euomphalus Decewi: Pleuronotus.137,138 
The Louisville limestones: Note on the Hydraulic beds and associated lime¬ 
stones at the Falls of the Ohio ..139-147 
Note on the Black Slate succeeding the Hamilton limestones at the Falls 
of the Ohio.148-154 
PTEROPODA, of the Palaeozoic formations.155-216 
Trntaculites : Historical sketch ........ F: 154-158 
Distribution of species.160-162 
Generic features and relations.163-166 
Descriptions of species.166-175 
Styliola : History, generic features and relations, and distribution ,. . 175-178 
Description of species . ..178-182 
Coleoprion : Historical sketch and description of species .... 183,184 
Coleolus : Generic features and descriptions of species.184-190 
