PLATE XXXIII. 

 Thamniscus multiramus. 



Page lOi. 

 Figs. 1-3. Specimens, natural size ; showing the foi'ra and mode of bi-anching'. 



Fig. 4. An enlargement of a portion of fig. 3. The surface is weather,eii or macerated, so that the re- 

 cumbent portions of the cell-tubes are shown ; a small part of the sui-face is preserved, show- 

 ing the form and arrangement of the cell apertures. 

 Fig. 5. An enlargement of the non-celluliferous side of a specimen, showing sharp striatious. (X 6-) 

 Upi>er Helderberg gi-oup. Schoharie, N. Y. 



Crisinella scrobiculata. 



I'age 103. 

 Fig. 6. A specimen, natural size, showing the form and mode of branching. 

 Fig. 7. An enlargement of a jjortion of the non-celluliferous side of fig. 6, showing fine strialions, and 



cell-tubes projecting beyond the margin. 

 Fig. 8. An eidargement of a portion of the celluliferous side of fig. 6, showing the form and arrangement 

 of cell apartui-es, and the shallow intei-cellular pits on a portion of the surface. 

 Upper Helderberg gi-oup. Wettern New York. 



Thamnotrypa DIVARICATA. 



Page 101. 

 Fig. 9. A specimen, natural size, showing the form and mode of branching. 



Fig. 10. An enlargement of a portion of one side of fig. 9, showing the non-celluliferous margins the 

 central ridge, and the form and arrangement of cell a{)ertni-es. 

 Upper Helderberg gi-oup. Near Buffalo, N. Y. 



Glauconome sinuosa. 



Page lul 

 Fig. 11. A specimen, natui-al size, 8howing the foi-m and mode of growth. hImii .um,; 



Fig. 12. An enlargement of a jmrtion of the celluliferous side of fig. 11, showing more distinctly the mode of 

 growth, the sinuous cariute, and the form and arrangement of the cell apertuivs. 

 Upper Helderberg group. Near Buffalo, N. Y. 



Glauconome nodata. 



Page :08. 

 Fig. 13. A 8j>ecimeu, natui-al size, showing the form and mode of branching, 



Fig. 14. An enlargement of a portion of the celluliferous side of fig 13, showing more distinctly the mode 

 of growth, the foi-m and aiTangemeiit of cell apertures. 



Upper Helderberg group. Ntdr Le Roy, N. Y. , 



