996 The American Naturalist. [December, 
permit a most heterogeneous assemblage of animals, whereas 
a disturbed and mountainous country divided into lofty pla- 
teaux, low savannahs and barricaded valleys would separate 
and isolate related groups, and from a low zoic maxima,’ in 
consequence of its irregularity and limited geographical scope, 
afford a meagre and less diversified fauna, and actually fewer 
fossils. The successful fossilization of the bones of terrestrial 
vertebrates can best be secured by their rapid burial within 
impervious beds of enveloping material wherein they undergo 
a slow process of partial or complete petrifaction. Nordens- 
kiold in his Voyage of the Vega discovered a very extensive 
deposit of whale bones in a sand dune upon a beach of Siberia 
in the Chuckchi country. These apparently had fallen to the 
bottom of a sea and were entombed by new layers and beds of 
sand. They were thus subfossil and possessed an immense 
age. Where they had become exposed by the violence of the 
waves they were decaying, but where buried in the sand the 
well preserved bones of these cetaceans were found in innum- 
erable quantities. 
The dispersal of bones in the ocean seems as unfavorable to 
their preservation as exposure on the surface of the earth or 
in the vegetable acids of its superficial covering. It is noto- 
rious that the dredging expeditions deputed to explore the 
depths of the oceans have seldom encountered the remains of 
vertebrate animals. The skeletons of whales, seals, porpoises 
and sharks have not been found commonly, though teeth 
brought up from these depths indicate the dissolution of the 
animals in the oceanic waters. So striking is this absence of 
osseous remains that Lyell remarks “there are regions at pres- 
ent, in the Indian and Pacific Oceans, coextensive in area with 
Europe and North America where we might dredge the bot- 
tom and draw up thousands of shells and corals without ob- 
taining one bone of a land quadruped.” 
è See AMER. NAT., Vol. XX, p. 1009. 
™ Some astonishment was created on board the ‘Challenger’ that the dredge 
after having dragged over miles and miles of the bottom of the sea, and up an 
down almost every oceanic basin, should never bring up any bones of fish or 
whale, or any remains of other large animals which inhabit the ses or whose 
bodies may have been carried down to the sea.” Thalassa, J. J. Wild, p- 133- 
