PLATE 12. 
Fig. 1. 80. ]. Column art a alveolata. (Pag. 47.) 
1. A vertical section of a compact specimen, showing the striated walls of the cells. 
I a. A vertical section, showing the transverse dissepiments, with the vertical lamellae obliterated. 
1 b. A transverse section (weathered surface), showing the radiating lamella'. 1 r. The same enlarged. 
Fig. 2. 81. 1. Stromatocerium rugosum. (Pag- 48.) 
2. A specimen, natural size, showing the concentric lamination of the coral. The masses are often several times 
as large as this one. 
2 a. A fragment magnified, showing less contortion of the laminae, with some indistinct indication of vertical 
tubes or cells. 
2 b. A small portion of a specimen of the natural size, showing the rugose or contorted direction of the lamina'. 
Fig. 3, 5. 82. 2. Chvetetes lycoperdon? (Pag. 48.) 
3. Specimen natural size. 
5. Probably the same species, very minute, occurring in some thin shaly layers at the upper part of the Bird¬ 
seye limestone, or at its junction with the Black-river limestone. 
Fig. 4. 83. 2. Streptelasma profunda. (Pag- 49.) 
4. Lateral view of a specimen where the edge of the cup is worn down, shortening the entire length about 
one-third. 
4 a. Section of a specimen near the base, showing the contortion of the lamellte at the centre : the section is 
slightly oblique. 
4 b. Transverse section above the base, showing the alternation of larger and smaller lamellae, which do not 
reach the centre. 
4 c. Transverse section near the termination of the cup. 1 have some doubt whether this section is of the 
same species, the lamellae being much stronger and less in number than in the other individuals, which 
all occur in one specimen of the stone. 
4 d. A longitudinal section, slightly oblique to the axis, and coming out on one side of the eentre below ; 
showing some of the lamellae vertically, and others obliquely. 
4 e. An oblique section, being nearly transverse to the lower part of the fossil on one side. 
Fig. 6, 7. 85. 4. Stictopora ramosa. (Pag-. -51.) 
tj. A small fragment of limestone, the surface covered with pieces of the coral. 
7. A small portion, showing the base of the cells when separated from the internal axis. 
7 n , The same magnified. 
Fig. 8. 84. 3. Stictopora labyrinthica. (Pag- 50.) 
3. The weathered surface of a fragment of the limestone, showing the transverse sections of this coral of the 
natural size. 
3 «, b. Enlarged portions as seen upon the specimen above, showing sections of two rows of cells rising ob¬ 
liquely from the axis. 
Fig. 9. Fragment of a crinoidal column. 
(Pag. 51.) 
