KOVEMBKE 23, 1900.] 



SCIENCE. 



787 



certain very undesirable changes in Linnsean 

 nomenclature, unavoidable under the rule 

 of elimination. Among these are the fol- 

 lowing : 



Esox for Bflone. 



Syngnathus for NeropMa. 



Polynemus for PeKtanemua. 



Meanwhile the confused generic messes 

 of Bloch, Lacepede, Swainson, Eafinesque 

 and others, could be definitely crystallized 

 and made to stand or fall on the generic 

 distinction of the first species named. 



The general adoption of such means of 

 determining types would go a long way to- 

 ward stability of nomenclature, and it is 

 possible to use it in case we may be per- 

 mitted to apply another method to the 

 genera of Linnaeus. If no exceptions can 

 be properly made, then, for one, the writer 

 would prefer its rigid application to all au- 

 thors, Linnaeus included, to the present 

 state of confusion. 



In any event, the suggestion of Mr. Cook 

 merits serious consideration and reconsider- 

 ation, for it has been several times rejected 

 by zoologists. 



David Starr Jordan. 



ADDRESS OF THE PRESIDENT OF THE SEC- 

 TION OF GEOLOGY OF THE BRITISH 

 ASSOCIATION. 



IL 



OBSCURE CHAPTER IN THE EARTH 's HISTORY. 



Before discussing the validity of the ar- 

 gument on which this last result depends, 

 let us consider how far it harmonizes with 

 previous ones. It is consistent with Lord 

 Kelvin's and Professor Darwin's, but how 

 does it accord with Professor Joly's ? Sup- 

 posing we reduce his estimate to fifty-five 

 millions ; what was the earth doing during 

 the interval between the period of fifty-five 

 millions of years ago and that of only 

 twenty-six and one-half millions of years 

 ago, when, it is presumed, sedimentary 

 rocks commenced to be formed ? Hitherto 



we have been able to reason on probabili- 

 ties ; now we enter the dreary region of 

 possibilities, and open that obscure chapter 

 in the history of the earth previously hinted 

 at. For there are many possible answers to 

 this question. In the first place, the evi- 

 dence of the stratified rocks may have been 

 wrongly interpreted, and two or three times 

 the amount of time we have demanded 

 may have been consumed in their forma- 

 tion. This is a very obvious possibility, 

 yet again our estimate concerning these 

 rocks may be correct, but we may have 

 erroneously omitted to take into account 

 certain portions of the Archaean complex, 

 which may represent primitive sedimentary 

 rocks formed under exceptional conditions, 

 and subsequently transformed under the 

 influence of the internal heat of the earth. 

 This, I think, would be Professor Bonney's 

 view. Finally, Lord Kelvin has argued 

 that the life of the sun as a luminous star 

 is even more briefly limited than that of 

 our oceans. In such a case, if our oceans 

 were formed fifty-five millions of years ago, 

 it is possible that after a short existence as 

 almost boiling water they grew colder and 

 colder, till they became covered with thick 

 ice, and moved only in obedience to the 

 tides. The earth, frozen and dark, except 

 for the red glow of her volcanoes, waited 

 the coming of the sun, and it was not till 

 his growing splendor had banished the long 

 night that the cheerful sound of running 

 waters was heard again in our midst. Then 

 the work of denudation and deposition 

 seriously recommenced, not to cease till the 

 life of the sun is spent. Thus the thick- 

 ness of the stratified series may be a measure 

 rather of the duration of sunlight than of 

 the period which has elapsed since the first 

 formation of the ocean. It may haye been 

 so — we cannot tell — but it may be fairly 

 urged that we know less of the origin, his- 

 tory, and constitution of the sun than of 

 the earth itself, and that, for aught we can 



