GEOLOGICAL CONTEMPORANEITY 377 



series of strata, containing organic remains, 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 arrangement ; so that the separate terms 

 of each series, as well as the whole series, exhibit a corre- 

 spondence. 



Succession implies time ; the lower members of a series of 

 sedimentary rocks are certainly older than the upper ; and 

 when the notion of age was once introduced as the equiva- 

 lent of succession, it was no wonder that correspondence 

 in succession came to be looked upon as a correspondence 

 in age, or " contemporaneity/' And, indeed, so long as 

 relative age only is spoken of, correspondence in succession 

 is correspondence in age ; it is relative 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 scries of strata. 



In anatomy, where such correspondence of position has 

 constantly 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 " homo- 

 taxis " (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 conclusions of their branch of biology 

 as that which has just been given. 



Our standard repertories 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 



