Xlii PEOCEEDIN-GS OF THE GEOLOGICAL SOCIETY. 



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 weR 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, 

 famihar, and part of our common language ? 



The reply to this question will become obvious as the inquiry 

 into the results of palaeontology is pushed further. 



Those whose business it is to acquaint themselves specially with 

 the works of palaeontologists, 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 palaeontology 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 

 the first of all living existences ; and to trace out the law of pro- 

 gress from them to us. 



It may not be unprofitable to bestow on these professions a some- 

 what more critical examination than they have hitherto received, in 

 order to ascertain how far they rest on an irrefragable basis, or 

 whether, after all, it might not be well for palaeontologists to learn 

 a little more carefully that scientific " ars artium," the art of saying 

 " I don't know." And to this end let us define somewhat more 

 exactly the extent of these pretensions of palaeontology. 



Every one is aware that Professor Bronn's * Untersuchungen * 

 and Professor Pictet's * Traite de Paleontologie ' are works of stan- 

 dard authority, familiarly consulted by every working palaeontologist. 

 It is desirable to speak of these excellent books, and of theij" distin- 

 guished authors, with the utmost respect and in a tone as far as 

 possible removed from carping criticism ; indeed, if they are spe- 

 cially cited in this place, it is merely in justification of the assertion 

 that the following propositions, which may be found implicitly or 

 explicitly in the works in question, are regarded by the mass of 

 palaeontologists and geologists, not only on the Continent but in this 

 country, as expressing some of the best-established results of palae- 

 ontology. Thus : — 



Animals and plants began their existence together, not long after 

 the commencement of the deposition of the sedimentary rocks, and 

 tUen. bucceeded one another in such a manner that totally distinct 



