PLATK I.VI_CoDtlnue<l. 



TitKMATOl'OKA (OuTIIOI'OKA) TOKTALINEA. 



i'tige ItiO. 

 Fig. 9. An enlarg-emeiit, showinjf the form and disposition of the cell apertures, and the sinuous, gi-anu- 

 lose ridjfes 8*!j)aratinff the rantjes of apertures. (X 18.) 



Hamilton gnmp. Wext Hamburg, EHe county, N. T. 



V 



Tkematotora (Oijthopoua) lineata. 



I'age 181. 

 See Plat* 55. 



Fig. 10. An enlargement, showing the form and disposition of the cell apertures, the extremely thin, 

 slightly ekniiled peristomes, and the pi-omineut, granulose ridges separating the ranges of 

 ai)ertui-es. (X 18.) 



Hamilton group. West Hamlmrg, Erie county, N. Y. 



' I <i I \r. i;i '{ 



TKEMATOrORA (0kTI1O1*OUa) IMMERSA. 

 Pago 18S. 

 Fig. 11. An enlargement, showing the form and disposition of the cell apertures, and the character of the 

 inlerapertural space. (X 18.) 



Hamilton group. M e.si Hamburg, Erie county, N. Y. 



Tre.matopora (Orthopora) interplana. 



I'agc 186. 

 Fig. 12. An enlargement, showing the form and disposition of the cell apertures, the slight pei-istomes, 

 and the Hat, graiiulose, interapertural space. (X 18.) 

 Hamilton group. Western New York. 



Trematopora (Orthopora?) tran.sversa. 



Page m. 



See Plate f,:>. 



Fig. 13. An enlargement, showing the form and disposition of the cell apertures, and the flat, granulose 



interapertural space. (X H.) 

 Fig. 14. A still farther enlargement, showing more distinctly the characters illustrated in fig. 13. 

 Hamilton group. West Hamburg, Erie county, N. Y. 



Trematopora (Orthopora) elonoata. 



Page \m. 

 See Plate 55. 

 Fig. 15. An enlargement, showing the fomi and disjxisition of the cell ai>ertui'es, the extremely thin peri- 

 stomes, and the granulose interapertural space. (X 18.) 



Hamilton group. Near the head of Owasco Lake, N. Y. 



Trematopora (Orthopora) uispinulata. 



Page ISi. 

 See Plate 55. 



Fig. 16. An enlargement, showing elongate-oval, regularly disposed cell apertures, the alternating nodes 



and prominent Umgituilinal ridges. (X 18.) 

 Fig. 17. An enlargement, showing somewhat broadly oval cell apertures, regularly disposed in longitudi- 

 nal rows, with two nodes between each two adjacent apertures, and sinuous longitudinal ridges. 

 (X 18.) 



Hamilton group. Darvn Centre, N. Y. 

 Fig. 18. An enlargement, showing indistinct cell apertures, prominent nodes and interrupted longitudinal 

 ridges. (X 18.) 



Hamilton gi-oup. Moscvw, Livingston county, N. Y. 



ACANTHOCI.EMA SOUTULATUM. 



Page 190. 



Sec Plate 55. 



tig. 19. An enlargement, showing regularly disposed cell apertures, and longitudinal ridges coalescing 



between the apertures, with nodes at their junction. (X 18.) 

 Fig. 20. An enlargement I'rom a slightly niaceiated specimen, showing regularly disposed cell apertures, 



strong longitudinal ridges, ami a node an<l pit between each two adjacent apertures. (X 18.) ' 

 Hamilton group. }Vest Hamburg, Erie county, N. Y. 



