I The American Geologist. January, 1896 
period than any intellectual revulsion of modern times. I );hi;i's 
altitude on another question applies equally well here. In the 
preface to the third edition of his mineralogy, in L850, he 
says that "To change is always seeming fickleness. Bui nol 
to change with the advance of science is worse; it is persis 
tence in error." 
The lirst edition of the Geology ( L862) clearly teaches the 
doctrine of special creation for the many successive floras and 
faunas in the geologic ages. It is now interesting to note the 
changes made in the wording of a single paragraph of this 
work through its separate editions. Others of a similar nature 
could be selected Imt the following is sufficient. In the gen- 
eral remarks at the (dose of the chapter on the Devonian age 
he says (1st ed., p. 304), "Each period had its new creations 
and its extinctions, and often, also, there were many succes- 
sive creations and extinctions in a single period." Twelve 
years afterward, while the law of evolution was being attacked 
on all sides, the corresponding paragraph of the second edi- 
tion (p. 2 ( s ( .» ) is noncommittal, merely stating the facts with- 
out any reference to the underlying cause, showing that the 
author was awaiting the result of the conflict and unwilling 
as a teacher to espouse either. It reads. '"Each period had its 
new species or tribes and its extinctions, and often, also, there 
were many successive faunas in a single period." The third 
edition is essentially the same here, though in other parts of 
the book advances are made toward the acceptance of the law. 
The last edition (1895) and the final work of his life is every- 
where built upon the central idea of evolution. It dominates 
and colors his entire thought and in the paragraph corres- 
ponding to the one already cited (4th ed., p. 630) we find that, 
••The progress of the systems of life through the Devonian era 
was continued into and through the following era without any 
abrupt transition. "" 
His willingness to modify his views in accordance with 
right methods and with the demands of science is further 
shown in his works on mineralogy. The System of Mineral 
ogy through its successive editions mirrors all the changing 
aspects presented by this science for more than half a century. 
Nothing could be more radical than the transition from the 
natural-historical system with its binomial nomenclature to 
