PLATE XXIV. 



ISCRADITES SQUAMIFER. 

 I'ago 290. 

 Fig. 1. A lateral ^^ew of the ty[ie specimen. The base is imiiei-fect. 



Fig. 2. A i«)rtion of the zonal surface eiilarg-ed, showing the imbricating aj)i)earance of the simimit 

 plates of the spicnlea. 



Lower Helderberg group. Schoharie, N. Y. 



Receptaculites infundibulifoumis. 



Page 289. 

 Fig. 3. A lateral view of a small silicified sjiecimen. 



Lower Helderberg group. Ulnrksmlle, N. Y. 

 Id. The upper side, showing the ai-raiigement of the summit jilates. 

 Id. An enlargement, showing a division of two of the vertical spicules, and the angulai- i:avities 



left by the solution of the summit plates. 

 Id. An oblique view of a portion of the Sui-face, showing the ajiinifei-ous ridges of the specimen. 

 Id. Similar to the preceding, but vertical to the surfac(!. 

 The summit of a larger specimen. 



The broken edge of the preceding, showing the cavities left by the vertical spicular rays. 

 A large specimen which has been marerated, corapi-essed, and the substance of the sponge 

 removetl. 



Lower Helderberg group. CJark-tinUe, N. T. 

 Fig. 11. A section similar to lig. 9, from a thin lenticalar specimen. 

 Lower Helderberg group. Clarksville, N. Y. 



ISCHADITES BUR8IFORMIS. 



X'age 24H). 

 Fig. 12. A lateral view of a large compressed specimen, preserving the impress of the calyces of three 

 cyathophylloid corals. 



Schoharie giit. Clarksville, N. Y. 

 Fig. 13. A small discoid compi-essed specimen with eccentric apex. 

 Fig. 14. A fragment, showing a different condition of weathering. 

 Schoharie jfriU Schoharie, N. Y. 



