16 The American Naturalist. [January, 
will soon be in the coming century, a more wonderful period | 
of Evolutionary Science will then open, than even that which 
has made this 19th Century conspicuous. And when these 
physiological processes do thus become the object of enthusi- 
astic research, at that moment will the rôle of “mind” begin 
duly, and necessarily to receive preponderating attention. 
This will happen the same, whether Parallelism remain the 
popular doctrine or not. Conduct is sure to be recognized, 
in time, as the major region of Physiological Biology; and 
“mind” is the chief source of conduct, whether the word im- 
ply “ molecular activities or “ psychic force.” 
This, then, in one word, is the summary of all our conclu- 
sions. Mind would not be mind save for its marvelous com- 
plexity. The basis of this emplexity is the variety of its sen- 
sory elements. These elements, or their physical equivalents, 
then, must be major factors of animal evolution; they must ex- 
plain the origin of mind; and they must play in Biology and 
Physiology all the part that mind unquestionably plays. To 
neglect them hereafter, either in Biology or in Psychology, is 
to neglect a major = and probably the major factor of both 
Sciences. 
FOSSILS AND FOSSILIZATION. 
By L. P. GRATACAP. 
HI 
(Continued from Vol. XXX, p. 1003.) 
Two very remarkable and instructive deposits of vertebrate 
remains which illustrate their placement, sepulture, and min- 
eralization, are represented in the tertiary beds of the Niobrara 
River in Nebraska, the lacustrine basins of Wyoming, in the 
United States,and the fluviatile plains of Argentina and Uru- 
guay in South America formed by the water-ways which pre- 
‘ceded and defined the present Parana, Paraguay, Uruguay 
and La Plata Rivers. In South America the Parana, Para- 
guay and Uruguay Rivers carry down vast amounts of sand, 
