334 T. C. CHAMBERLIN 



In any attempt to rectify the criteria, there is a prerequisite 

 that is strictly indispensable, to wit, the keen recognition that 

 relics buried beneath secondary or tertiary derivatives from the 

 surficial deposits are little better than Mephistophelian in their 

 insidious power to deceive. A relic reported as found beneath 

 twelve feet of gravel or twenty feet of loess by anyone not trained 

 to avoid these Mephistophelian lures is to be held as quite without 

 value until tested; it merely serves as an interrogation point to 

 punctuate the question. Is it worth while to investigate the case ? 



c) The deeper and broader issues involved in the Vero case. — The 

 more profound interest of studious men of science lies in such 

 advances in modes of inquiry, such increases in the trustworthi- 

 ness of criteria, such larger hospitality to working alternatives, 

 such greater readiness to make trial of these and frankly lay .them 

 aside if found wanting; such hospitality to revision, and such 

 larger views of the whole problem as may be drawn out from the 

 case. Let us therefore survey from a more general point of view 

 the main lines along which this problem may be approached with 

 the hope of important light. Foremost among these are: (i) the 

 extinction of biotic species; (2) the introduction of biotic species; 

 (3) the physico-dynamic vestiges; and (4) the regional relations 

 of the formations; the rest must be omitted. The leading 

 criterion of the first is life gone out; of the second, life come in; 

 of the third, work done; and of the fourth, the deployment of the 

 record. 



(i) In approaching a problem on the first line, it has been 

 customary to bring to bear the times of extinction of the species 

 of faunas and floras that lived in the stages immediately preced- 

 ing and the ratios of such extinct forms to the living species 

 present. Some advances on the older methods are to be noted. 

 Chief among these is the appeal to causes of extinction as con- 

 firmatory evidences. This relates the statistical method to the 

 dynamic method; it helps to co-ordinate the facts of extinction 

 with the work of the agencies that produce extinction. This 

 has chiefly been a co-ordination of faunal changes and glacial 

 climates. Further deployment in this and other directions is much 

 to be desired. As a suggestion in that line, why should not the 



