PLATE XXIV. 
ISCHADITES SQUAMIFER. 
Page 290. 
Fig. 1. A lateral view of the type specimen. The base is imperfect. 
Fig. 2. A portion of the; zonal surface enlarged, showing the imbricating appearance of the summit 
plates of the spicules. 
Lower Helderberg group. Schoharie, N. Y. 
Eeceptaculites tnfundibuliformis. 
Page 2S9. 
Fig. 3. A lateral view of a small siliciiied specimen. 
Lower Helderberg group. Clarksville, JST. Y. 
Fig. 4. Id. The upper side, showing the arrangement of the summit plates. 
Fig. 5. Id. An enlargement, showing a division of two of the vertical spicules, and the angular cavities 
left by the solution of the summit plates. 
Fig. 6. Id. An oblique view of a portion of the surface, showing the spiniferous ridges of the specimen. 
Fig. 7. Id. Similar to the preceding, but vertical to the surface. 
Fig. 8. The summit of a larger specimen. 
Fig. 9. r i ’’he broken edge of the preceding, showing the cavities left by the vertical spicular rays. 
Fig-. 10. A large specimen which has been macerated, compressed, and the substance of the sponge 
removed. 
Lower Helderberg group. Clarksville, N. Y. 
Fig-. 11. A section similar to tig. 9, from a thin lenticular specimen. 
Lower Helderberg group. Clarksville, N. Y. 
ISCHADITES BURSIFORMIS. 
Page -290. 
Fig. 12. A lateral view of a large compressed specimen, preserving the impress of the calyces of three 
cyathophylloid corals. 
Schoharie grit. Clarksville, N. Y. 
Fig. 13. A small discoid compressed specimen with eccentric apex. 
Fig. 14. A fragment, showing a different condition of weathering. 
Schoharie grit. Schoharie, N. Y. 
