PLATE XXVI—Continued. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Callopora (Ccelocaulis) aculeolata. 
Page 76. 
16. A specimen, natural size, somewhat crushed. 
17. An enlargement of fig. 16, showing the form and arrangement of the cell apertures, th .minute 
spines on the elevated peristomes and the intermediate pits. (X 6.) 
Upper Helderberg group. New York. 
Callopora multiseriata. 
Page 75. 
See Plate 25. 
18. A specimen, natural size, showing the manner of growth. 
19. An enlargement of fig. IS, showing the form and arrangement of the cell apert.U 1 ‘ and the 
intermediate pits, so arranged as to give a striated appearance to the surface. f 
Upper Helderberg group. Near Le Roy, N. Y. 
Lichenalia permarginata. 
Page 82. 
20. An enlargement, showing the form and arrangement of cell apertures. A single4nacula destitu 
of cells, and the larger cell apertures immediately surrounding it. (X 6.) 
Upper Helderberg group. Onondaga Valley, N. Y. 
21 . 
22 . 
27. 
Lichenalia (Pileotrypa) denticulata. 
Page 84. 
See Plate 30. 
A specimen, natural size, incrusting a Fenestella. 
An enlargement of a portion of the specimen, showing the form and arrangement of cell apertures 
and maculae of larger cells. (X 6.) 
An enlargement of a portion of the surface of a specimen, showing the cells nearly para!' .,'Uh 
the surface, and maculae destitute of cell apertures. The apertures contiguous to the ulae 
indistinctly radiate from them. 
Upper Helderberg group. Falls of the Ohio river. 
.0 
Lichenalia subcava. 
of 
Page 81. 
23. A specimen, natural size. 
24. A natural section, showing the hollow spaces beneath the elevated maculae. 
25. An enlargement of a portion of fig. 23, showing the form and arrangement of cell a] res, 
and appearance of the elevated maculae. 
Upper Helderberg group. Falls of the Ohio river. 
Lichenalia substellata. 
Page 78. 
See Plate 30. 
26. An enlargement of a portion of the surface, showing the form and arrangement of cell apertures. 
One of the sterile maculae, in the center of the figure, shows the adjacent cell apertures larger 
than the others and radiating from it. 
Upper Helderberg group. Falls of the Ohio river. 
,1 
