Zero of Animal Life probably about 300 fathoms.
As we descend deeper and deeper in this region its inhabitants become more and more modified, and fewer and fewer, indicating our approach towards an abyss where life is either extinguished, or exhibits but a few sparks to mark its lingering presence.
Moreover, all our knowledge of organic remains teaches us, that species have a definite existence, and a centralization in geological time as well as in geographical space, and that no species is repeated in time.
