126 THE DEVONIAN AND CARBONIFEROUS. [bull. 80. 



To " the topsyturvy appearance of the three species of Spirifera which 

 outside of Pennsylvania have been found (1) never in any but Chemung 

 rocks ; (2) confined each to its own horizon ; and (3) always in a fixed 

 order from above downwards;" 1 and also to the high reported range of 

 several species. The objections were so pointed that the State geolo- 

 gist, J. P. Lesley, closed his letter with the statement that " the start- 

 ling fossil species of this report will therefore baregarded by the pale- 

 outological reader as only provisionally verified," etc. 2 



Two things about the report were out of the ordinary and expected 

 line of opinion. The author, though i^artly recognizing the lithology 

 as worthy of consideration, based his classification of these " subcon- 

 glomerate v rocks on the evidence of the fossils and secondly he classified 

 the rocks according to the evidence and not according to the standards 

 as they existed in New York State. He was forced to recognize two 

 " transition v groups in order to suit both kinds of evidence. This sat- 

 isfied neither the lithologic nor the paleontologic schools of geologists. 



The identification of fossils may not have been accurate in all cases, 

 but the result of later studies has clearly shown that the real difficulty 

 was not in the identification but in interpretations which were brought 

 out by the facts. The minute and exhaustive field work of the second 

 Pennsylvania survey had shown beyond the possibility of contradiction 

 that geologic formations vary within wide limits in their lithologic 

 character and in their thickness, and constantly, so that sections a few 

 miles apart may present very little in common, although known to be 

 stratigraphically correlative with each other. This had led to the full 

 adoption of the idea that the parallelism of strata must be made by 

 actual traciug of the strata from place to place, and that identification 

 by lithologic likeness was impracticable over any considerable interval 

 of space. Paleontologists, however, still clung to the theory of the 

 strict uniformity of sequence in faunas. 



The " canonical n opinion of the " highest authorities " in paleon- 

 tology was that the order of sequence in species of fossils, established 

 by the facts in one well authenticated section of deposits, furnished a 

 standard that could be implicitly relied upon in the correlation of other 

 sections. When it was reported that this established order was not 

 preserved, doubt w T as naturally cast upon the identification of the fos- 

 sils. 



The Pennsylvania geologists did not seem to be aware of the impor- 

 tance of the facts, but they were correct and the error lay in the theory 

 of the paleontologists. 



Mr. Claypole, 3 in defense of his statements embodied in the Pennsyl- 

 vania report, and criticised by Mr. Hall in the preface of the same 

 volume, quoted from an article of Mr. Williams's, in which are recorded 

 observations confirming his statements in Report G 7 . 



1 Rept. of Prog. G 7 , p. xx. 2 Ibid., p. xxvi. 



3 Claypole, E. W. : On tho vertical range of certain fossil species in Pennsylvania and New York. 

 Am. Naturalist, vol. 19, pp. 644-654. 



