GEOLOGICAL CONTEMPORANEITY 383 



in any given vertical linear section of an undisturbed series 

 of sedimentary deposits, the bed which lies lowest is the 

 oldest. In many other vertical linear sections of the same 

 series, of course, corresponding beds will occur in a similar 

 order ; but, however great may be the probability, no man 

 can say with absolute certainty that the beds in the two 

 sections were synchronously deposited. For areas of 

 moderate extent, it is doubtless true that no practical 

 evil is likely to result from assuming the corresponding 

 beds to be synchronous or strictly contemporaneous ; and 

 there are multitudes of accessory circumstances which 

 may fully justify the assumption of such synchrony. 

 But the moment the geologist has to deal with large areas, 

 or with completely separated deposits, the mischief of 

 confounding that " homotaxis " or " similarity of arrange- 

 ment," which can be demonstrated, with " synchrony " 

 or " identity of date," for which there is not a shadow of 

 proof, under the one common term of " contemporaneity " 

 becomes incalculable, and proves the constant source of 

 gratuitous speculations. 



For anything that geology or paleontology are able 

 to show to the contrary, a Devonian fauna and flora in 

 the British Islands may have been contemporaneous with 

 Silurian life in North America, and with a Carboniferous 

 fauna and flora in Africa. Geographical provinces and 

 zones may have been as distinctly marked in the Paleozoic 

 epoch as at present, and those seemingly sudden appear- 

 ances of new genera and species, which we ascribe to ne^ 

 creation, may be simple results of migration. 



It may be so ; it may be otherwise. In the present 

 condition of our knowledge and of our methods, one verdict 

 " not proven, and not proveable " must be recorded 

 against all the grand hypotheses of the paleontologist 

 respecting the general succession of life on the globe. The 

 order and nature of terrestrial life, as a whole, are open 

 questions. Geology at present provides us with most 

 valuable topographical records, but she has not the means 

 of working them into a universal history. Is such a 

 universal history, then, to be regarded as unattainable ? 

 Are all the grandest and most interesting problems which 

 offer themselves to the geological student essentially 

 insoluble ? Is he in the position of a scientific Tantalus 

 doomed always to thirst for a knowledge which he 

 cannot obtain ? The reverse is to be hoped ; nay, it may 



