188 WALKS AND TALKS. 



shell is divided by cross partitions or septa at frequent intervals. 

 Like Nautilus, it is a gradually tapering tube. Like Nautilus, 

 there is near the center of each septum, a small perforation 

 from which leads a little tube to the next septum, and thus 

 through all the septa and intervening chambers. \This tube is 

 the siphuncle.^) Like Nautilus, each septum is simply and 

 plainly concave with the concavity turned toward the larger 

 end of the shell. As in Nautilus, the last chamber is deep, 

 and undoubtedly this was the portion to which the animal 

 was confined. If Nautilus should be uncoiled, it would be 

 precisely an Orihoceras. 



How the relics of these interesting creatures lie packed in 

 various parts of the Niagara limestone through all its conti- 

 nent-wide extent often broken, sometimes perfect. There is 

 no consciousness in these ruins now. We can picture them, 

 however, the homes of creatures which could feel and see and 

 hunger and desire, and entertain a purpose. We can think 

 back the wide-ten tacled bodies which rested in the outer 

 chamber. We can see them, in thought, spreading their 

 strong arms, glaring with their great glassy eyes, pursuing 

 with hungry ferocity their prey, tearing with their lance-like 

 mandibles, and feeding with the gusto and relish of a true 

 carnivore. 



We notice among the dead chambered shells some varia- 

 tions. In form, a few are slightly bent, while most are 

 straight. In some, the traverse section is oval, while generally, 

 it is almost circular. In some, the place of the siphuncle, in- 

 stead of being central, is a little distance away from the 

 center but not in the margin. We notice, also, that the 

 septum is sometimes undulate around the margin, instead of 

 plane. Thus nature shows a susceptibility to vary. Her 

 forms are fashioned after fundamental plans, but not all cast 

 in one mould. For some reason which may be inscrutable, 

 she seems always playing off from the main path, with a 

 sense of freedom rather than necessity. 



Right here, in the midst of these ancient Orthoceratites, 

 are the relics of organisms decidedly divergent. Here are 



