THE INTRODUCTION OF NEW SPECIES, 13 
in geographical proximity. The question forces itself 
upon every thinking mind,—why are these things 
so? They could not be as they are had no law 
regulated their creation and dispersion. The law 
here enunciated not merely explains, but necessitates 
the facts we see to exist, while the vast and long- 
continued geological changes of the earth readily 
account for the exceptions and apparent discrepan- 
cies that here and there occur. The writer’s object 
in putting forward his views in the present imper- 
fect manner is to submit them to the test of other 
minds, and to be made aware of all the facts 
supposed to be inconsistent with them. As his 
hypothesis is one which claims acceptance solely 
as explaining and connecting facts which exist in 
nature, he expects facts alone to be brought to dis- 
prove it, not a priort arguments against its pro- 
bability. 
Geological Distribution of the Forms of Life. 
The phenomena of geological distribution are ex- 
actly analogous to those of geography. Closely allied 
species are found associated in the same beds, and 
the change from species to species appears to have 
been as gradual in time as in space. Geology, how- 
ever, furnishes us with positive proof of the extinc- 
tion and production of species, though it does not 
inform us how either has taken place. The extinction 
of species, however, offers but little difficulty, and 
the modus operandi has been well illustrated by Sir 
