300 The American Geologist. cio <= 
portions the organic results might be also appreciably similar. 
Is it an insupportable speculation that such a thing as simul- 
taneous faunas are possible and that the biological processes 
which originated a faunal expression in one place might pro- 
duce one resembling it in another if the physical constants 
were the same? 
The statement baldly made does seem difficult to accept. 
And yet thrown into more generalized form as applicable to 
groups, families, or generic resemblances, it is entirely reason 
able. 
It assumes that evolution is omnipresent, working inces- 
santly upon animal forms, through the slow accumulation of 
differences, or possibly by even abrupt changes which repre- 
sent the accommodation of the organism to new requirements, 
or suddenly introduced environmental differences. The homo- 
geneity of nature remains unassailed if we accept simultaneous 
consequences in its different areas under identical conditions. 
It is even cognizable as a true proposition, at least in theory, 
that evolution has produced a number of origins, and that the 
faunal population of the world was the result of the approx- 
imating edges of great faunal patches which started at dif- 
ferent points under the fecund influence of this persistent, per- 
vasive, brooding agency of biological progress. Such con- 
clusions are easily affirmed and demonstrated in land faunas 
and, in so far as there could be segregation in the early 
oceans, it seems also a feasible proposition there. 
The Cambrian faunas of Bohemia, Sweden, Norway, and 
of eastern North America, might be regarded as disconnected 
simultaneous faunas, while in North America itself the Aca- 
dian western and southern Cambrian provinces are, not incon- 
ceivably, quite disparate and isolated faunal facts, in spite of 
all assumed stratigraphical relations. 
And in this connection we are also as logically permitted 
to assume that this inexorable evolution may act with more 
certainty and speed in some areas than in others. This has 
been however frequently suggested. The imaginative picture 
thus presented is not unlike this. 
We have in one section of a universal ocean a fauna fol- 
lowing its formal tendencies under conditions of acceleration, 
in another section a similar fauna responding more slowly to 
