514. ANNIVERSARY ADDRESS TO THE GEOLOGICAL SOCIETY 
an induction from a vast number of observations, though it may 
possibly, and even probably, have to admit of exceptions. As a 
consequence of the second law, it follows that a peculiar relation 
frequently subsists between series of strata, containing organic re- 
mains, in different localities. The series resemble one another, not 
only in virtue of a general resemblance of the organic remains in the 
two, but also in virtue of a resemblance in the order and character 
of the serial succession in each. There is a resemblance of arrange- 
ment; so that the separate terms of each series, as well as the whole 
series, exhibit a correspondence. 
Succession implies time; the lower members of a series of sedi- 
mentary rocks are certainly older than the upper; and when the 
notion of age was once introduced as the equivalent of succession 
it was no wonder that correspondence in succession came to be 
looked upon as correspondence in age, or “ contemporaneity.” And, 
indeed, so long as relative age only is spoken of, correspondence in 
succession zs correspondence in age; it is ve/atzve contemporaneity. 
But it would have been very much better for geology if so loose and 
ambiguous a word as “contemporaneous” had been excluded from 
her terminology, and if, in its stead, some term expressing similarity 
of serial relation, and excluding the notion of time altogether, had 
been employed to denote correspondence in position in two or more 
series of strata. 
In anatomy, where such correspondence of position has con- 
stantly to be spoken of, it is denoted by the word “homology” and 
its derivatives ; and for Geology (which after all is only the anatomy 
and physiology of the earth) it might be well to invent some single 
word, such as “ homotaxis” (similarity of order), in order to express 
an essentially similar idea. This, however, has not been done, and 
most probably the inquiry will at once be made—To what end 
burden science with a new and strange term in place of one old, 
familiar, and part of our common language? 
The reply to this question will become obvious as the inquiry 
into the results of paleontology is pushed further. 
Those whose business it is to acquaint themselves specially with 
the works of paleontologists, in fact, will be fully aware that very 
few, if any, would rest satisfied with such a statement of the con- 
clusions of their branch of biology as that which has just been given. 
Our standard répertoires of paleontology profess to teach us far 
higher things—to disclose the entire succession of living forms upon 
the surface of the globe; to tell us of a wholly different distribution 
of climatic conditions in ancient times; to reveal the character of 
