CONCLUSIONS 851 



curred in two similar but distinct zones — one with the Platycrinus, the 

 other without it and higher, presumably in the Gasper part of the Monte- 

 sana limestone. The work of the past summer shows that there is only 

 one zone, and that the supposed Gasper crinoids occur, like those listed 

 in 1917 as found on the same slabs with Platycrinus liuntsviUce, in the 

 main Platycrinus zone, which lies only a few feet beneath the base of the 

 Gasper. 



Conclusions 



With a single non-essential amendment and certain added facts, the 

 "concluding statement" in my 1917 Kentucky Eeport (page 190) will 

 do as well for this paper. As revised, it reads as follows : 



"In the foregoing pages I have applied and verified means of correlating 

 geological formations — correlation by stratigraphic position, by lithologic simi- 

 larity, by sequence of like lithologic units, faunas, and geologic events, by 

 paleogeographic probabilities, by evolutional stages of species and faunas, by 

 comparison of generalized faunal aspects, and by the more direct and precise 

 matching of faunas, species, and particularly of systematically subordinate 

 mutations of complexly constructed organic remains. The result in each trial 

 has been as definite as the particular means employed permitted, and in every 

 instance the predominant trend of the evidence has been clearly and uniformly 

 favorable to the views here advocated. Such continuous corroboration would 

 be impossible if my conclusions were not firmly grounded on incontrovertible 

 facts and, in essential respects, absolutely true. 



"Whereas the relatively generalized criteria chiefly relied on hitherto may 

 have left some room for legitimate argument, the more definite and positive 

 nature of most of the new data presented in this paper has destroyed all 

 chance for logical and successful refutation. So far as it may be done with 

 the material and methods available, the case [referring to the base of the 

 Chester series, the inclusion of the Upper Ohara in the Sainte Genevieve 

 formation, and the age relations of the Upper Ohara to the Renault] is settled. 

 It can be unsettled again only by discrediting paleontological evidence in 

 correlation ; but that would be nothing short of stratigraphical suicide, for 

 after all it is on the fossils that we mainly rely in establishing the time 

 relations of geological events. If paleontological correlations have sometimes 

 proved erroneous or imperfect, the fa alt has not lain with the fossils, but 

 with the paleontologist who endeavored to interpret their testimony. Studied 

 in minutest detail and determined and matched as critically as possible, the 

 fossils tell the story both truly and fully. 



"I have conscientiously endeavored to fulfill these requirements in the 

 present case; and I claim, therefore, that in all essential respects the con- 

 clusions reached are in harmony with the facts : 



"(1) The upper Gasper corresponds to the Ridenhower shale, and both to 

 the Paint Creek formation. (2) The lower Gasper represents the Renault 

 formation, and the sandstone directly beneath the Gasper is the correlative of 

 [or, rather, occupies the same position in the section as] the Aux Vases sand- 



