PLATE LXIXYII, 
Orthoceras Eriense. 
Page 274. 
See Plate 40. 
Pig-. 1. The chamber of habitation of an individual referred to this species. The specimen is somewhat 
broken from compression, and the test has been replaced and the surface-markings obliterated 
by iron pyrites. 
Fig. 2. A septum from the preceding specimen, showing the position of the siphuncle and the amount of 
compression. 
Othoceras linteum. 
Page 277. 
Fig. 3. A fragment, preserving a portion of the chamber of habitation, with the last air-chamber, showing 
the surface-markings over the entire tube. Leonardsville, Madison county, N . Y. 
Fig. 4. A portion of the surface enlarged four diameters to show the character of the striae. 
Orthoceras, sp. undetermined. 
Figs. 5, 6. Two figures representing a not uncommon condition of preservation of the fossils in the softer 
shales. The shell has evidently been macerated, and surrounded by a concretionary mass of 
of the clay forming the shale—the whole being subjected to compression. From the effects of 
compression, and the mode of accretion, the specimens are often regularly striated, as repre¬ 
sented in these figures; and in two specimens of 0. subulatum, illustrated on plate 84, exhibit 
the same conditions in the anterior air-chambers : giving the appearance termed “ slickensides.” 
The specimen, figure 5, is from the soft shales at Pratts Falls, Onondaga county, N. Y, 
and the larger one is found in a similar situation at Eighteen-mile Creek, on Lake Erie /Shore, 
near Buffalo, N. Y. 
