670 REPORT OF NATIONAL MUSEUM, 1904. 



should be older than the Taconic proper, and therefore that his Taconic 

 .system was actually newer than the fossiliferous rock. This evidently 

 being to his (Emmons's) mind impossible, he was thence led to think 

 out a way by which rocks might dip eastward and still be newer to the 

 westward and that, ""without a fact or even an argument to sustain it, 

 he announced in his agricultural report, published in 1843, this as the 

 true order. He thus, by a stroke of his pen, tipped over the Taconic 

 system and got the black slate to the top with all other Taconic rocks 

 beneath it." 



This black slate interpolation in 1S43, according to Dana, thus 

 brought mischief to the Taconic system and to much American 

 geology and was styled by him "a most desperate blunder." Bil- 

 lings's work he regarded as eliminating the black slates from the 

 system. Dana went on to state that the quartzite, which in the pub- 

 lication of 1842 occurred toward the middle of the section, was, in that 

 of 1843, placed at the bottom of the Taconic series. Hence in this 

 "perfected Taconic" the rocks which Billings had shown to be nearest 

 to the pre-Silurian of all the Taconic beds were thus placed at the 

 remote ends of the system, the black slate at the top and the quartzite 

 at the bottom, the former being of Primordial age and the only rock 

 series which had yet proven to be pre-Potsdam. 



Dana acknowledged that Emmons was deserving of honor for com- 

 bating the old idea which had prevailed among geologists and paleon- 

 tologists, to the effect that the Taconic slates belong to the Hudson 

 River period; yet he contended that he ''blundered in everything 

 else," determining nothing correctly as regarded the age or order of 

 succession of the rocks of the system, and "his assumptions after 1S42 

 were so great as to order of stratification and faults, and his way of 

 sweeping distant rocks into his system so unscientific, that his oppo- 

 nents had abundant reasons for their doubts/' He went on to say 

 that no one knew, even at that date, what the precise age of the slates 

 of the Taconic Mountains might be. although Logan's view that they 

 belong to the Quebec seemed nearest the truth. The only way, he 

 argued, for geologists to get out of the Taconic perplexity was to go 

 back to Emmons's original report and section of 1842. "The name 

 Taconic," he wrote, " belongs only to the era represented by the rocks 

 of the Taconic Mountain," and nowhere else. 



In a series of articles in the American Journal of Science, beginning 

 with December of 1872. Dana showed the conforinability of the 

 Taconic slates and schists of the Taconic Mountains and the Stock- 

 bridge limestone and quartzite, and on the basis of the discoveries of 

 Wing and Billings, pronounced the limestone to be of Trenton and 

 ( "hazy age and the schists and slates to be of Hudson River age, in 

 this agreeing with Rogers. He also pointed out that the same beds of 

 metamorphic rocks might vary as do their unconsolidated representa- 



