184 STUDIES IN GEOLOGY, No. 3 



PLATE IV. 



Figs, i, 2, 3. Turritella prenuncia Spieker. 



1. x 3 . 



2. X5. 

 3- X2. 



4. Turritella prenuncia var. inconspicua Grzybowski, x2. 



5. Turritella robusta Grzybowski . 



6. Turritella robusta var. abrupta Spieker. 



7. Turritella charana Spieker. 



8. Polynices subangulata Nelson. 



9. Polynices porcana Spieker. 



10. Sinum carolannm Spieker, x5. 



11. Turbo belli Spieker, x2. 



12. Turbo belli var. aequifilicatus Spieker. 



13. Cancellaria (Aphera) peruana Nelson, x2. 



