(Magnified 500 diameters, except Fig. 1, which is enlarged 250 



diameters.) 



Figs. 1-13. Sponge spicules. Croton Point. 



Fig. 14. Melosira granulata (Ehr.) Ralfs. Croton Point. 



Fig. 15. JSfamcula Grue?ideleri> A. S. Croton Point. 



Fig. 16. Diatoma sp ? Plattsburg. 



Fig. 17. Diatom fragment from Croton Point. 



Fig. 18. ISTavicula per magna, Edw. Croton Point. 



Figs. 19, 20. Sponge spicules. Kreischerville, S. I. 



Figs. 21, 22, 23, 24. From clay at Verplank. 



Fig. 25. Kitszchia granulata, Grun. Croton Point. 



Fig. 26. From clay at Croton Point. 



