PLATE IX. 



CRISINELLA. 



(Page 526.) 



CfilSINELLA. SCEOBICULATA, Hall. 



Fig. 1. A portion of a frond, natural size. 

 Fig. 2. Noncelluliferous face. x6. 

 Fig. 3. Celluliferous face. x6. 

 Upper Helderberg group. 



THAMNICELLA. 



(Page 525.) 



TflAMNICELLA NySA, Hall. 



Fig. 4. A fragment, natural. size. 

 Fig. 5. The same. x6. 



Lower Helderberg group. Clarhsmlle^ N, Y. 



Thamnicella ascuta, Hall. 



Fig. 6. A fragment, natural size. 



Fig. 7. A portion of the celluliferous face. x9. 



Fig. 8. A portion of the noncelluliferous face. x9. 



Thamnicella Cisseis, Hall. 



Fig. 9. A frond, natural size. 



Figs. 10, 11. A portion of the noncelluliferous face. x6. 

 Fig. 12. A portion of the celluliferous face. x6. 



Fig. 13. A group of Bryozoa, among which are several specimens of 

 this species. 

 Lower Helderberg group. Clarksville, JV, Y. 



THAMNISCUS. 



(Page 524.) 

 Thamniscus variolata. Hall. 

 Fig. 14. A fragment of the noncelluliferoas face of a frond. x3. 



Thamniscus Niagarensis, Hall. 



Fig. 15. A frond, natural size. 

 Fig. 16. A portion of the celluliferous face, x2. 



Fig. 17. A portion of the celluliferous face of another specimen, 

 showing angular, carinated branches. 

 Niagara group. Waldron, ladiana. 



636 



