PLATE 13. 



J^ENESTELLA (PoLYPOEA) LATITRUNCATA; 



Fi&s. 1-9. 

 Penestella {Polypora) latitruncata, Hall. Keport of State Geologist fot* 



1886, page 68. 



Fig. 1. A fragment of the non-celluliferoiis face, natural size. 



Fig. 2. A fragment of the celluliferous face, natural size. 



Fig. 3. A fragment from another specimen, natural size. 



Fig. 4. An enlargement from the non-celluliferous face, showing some-- 



what distorted branches. 6 x. 

 Fig. 5. An enlargement showing slender branches and irregularly formed 



fenestrules. 6 x. 

 Fig. 6. An enlargement showing stronger branches and more irregularly 



formed fenestrules. 6 x. 

 Fig. 7. An enlargement from the celluliferous face, showing the form and 



disposition of the cell apertures. 6 x. 

 Fig. 8. An enlargement, showing twisted striations. 6 x. 

 Fig. 9. An enlargement, shoAving very thin branches and large variable 



fenestrules. 6 x. 



Fenestella (Polypora) aspectans. 



Figs. 10-14. 



Fenestella {Polypora) aspectans, Hall. Keport of State Geologist for 1886, 



page 65. 

 Fig. 10. A fragment, natiiral size. 

 Fig. 11. An enlargement from the non-celhiliferous face, showing nearly 



circular fenestrules. 6 x. 

 Fig. 12. An enlargement from the celluliferous face, showing the form and 

 disposition of the cell apertures and the extremely narrow 

 fenestrules. 6 x. 

 Fig. 13. A transverse section of the branches, showing their cuneiform 



shape. 6 x. 

 Fig. 14. An enlargement of a lateral view of a branch, showing the form 

 of the dissepiments and the position of the cell apertures. 



