PLATE 84. 
Fig. 1. 369. 4. CyRTOLITEs ORNATUS. (Pag. 308.) 
1 a. Lateral view of a cast of this species, 1b. Profile of the same, looking into the aperture. 
le, Another specimen (a cast), where the volutions are contiguous. 
1d, A specimen preserving the shell, from which the finer strie are removed. 
1e. A portion of the surface of the shell, showing the sculpture. if. Part of the same magnified. 
1 g. A transverse section of the shell. 
Fig. 2. 249. 1. TRocHoLITEs AMMONIUs. (Pag. 309.) 
2a, A small specimen, partially preserving the shell in some parts, and showing the septa in others. 
2. An enlarged portion of the surface, which is partially exfoliated, and slightly different from similar mag- 
nified parts of those in the Trenton limestone, where the shell is well preserved. 
2c. Mould of a large specimen in the black slate. 
Fig. 3. 370. 2. 'TROCHOLITES PLANORBIFORMIs. (Pag. 310.) 
3 a. Figure of a specimen nearly entire. 3 6. Dorsal view of the same. 
3c. Ventral view of a fragment, preserving part of the two outer volutions, showing the concave ventral side, 
and the position of the siphuncle. 
3 c*. Section of the outer volution. 3d. A portion of the surface magnified. 
3 e. A specimen crushed in a vertical direction, a part of the outer volution retaining its form. 
3 f. Dorsal view of the same, showing the slightly arching septa upon the dorsal line, and a part of the outer 
chamber. 
