J. D. Dana— Brief history of Taconic ideas. 419 



Olenus belong to his Primordial zone or are Sub-silurian in 

 Bohemia. In this respect our Paradoxides are also Sub- 

 silurian : and hence it has been shown that the Primordial 

 zone in Bohemia is in coordination with the upper series of the 

 Taconic rocks." . Professor Emmons's letters to Mr. Marcou 

 written in 1860 and published by the latter in the Proceedings 

 of the American Academy for 1884, show that he meant here 

 to emphasize u Upper" Primordial; for he protests that only 

 a small part of his system is coincident with Barrande's Pri- 

 mordial. 



1860 to 1863.— The years 1860 to 1863 were epochal in Ta- 

 conic History. Great light was let in upon the system by 

 letters of August, 1860, from Barrande, the eminent paleon- 

 tologist of the Silurian of Bohemia, addressed to Professor 

 Bronn of Heidelberg and Mr. Marcou of Cambridge, Mass., 

 and also from a memoir read by him before the Geological 

 Society of France. Having before him the figures and descrip- 

 tions of the Georgia trilobites, referred to above, received from 

 Mr. Billings, he pronounced them unquestionably Primordial, 

 thus confirming the decision of Professor Emmons just men- 

 tioned. 



But Barrande, adopting in his Memoir in full the views of 

 Emmons on the Taconic system, and regarding the Primordial 

 fossils as really characteristic of a great Taconic system of rocks 

 extending far below the Olenus or Paradoxides zone, speaks of 

 the Taconic as the American Primordial — his own system under 

 unusual development — a view not satisfactory to Professor 

 Emmons, for he had in contemplation for his Lower Taconic 

 much greater depths, something like the unsounded Huronian, 

 equivalency with which he thought he could make out.* And 

 thus confusion was introduced by Barrande along with the 



* Barrande's letters are addressed — Paris, July 16, 1860, to Professor Bronn of 

 Heidelberg, and August 14th, 1860, to M. J. Marcou. Tbey were read before the 

 Boston Soc. Nat. Hist, in October, 1860, and are published in the Proceedings, 

 vol. vii, 371 ; also in this Journal, H, xxxi, 210, 1861, with an omission of Mr. 

 Marcou's name because of its unmentioned omission on the part of the sender 

 (from Canada) of the communication ; also in the Geol. Rep. Vermont (with the 

 same omission) p. 377 ; and also, with other letters, in Mr. Marcou's paper in the 

 Proc. Amer. Acad., vol. xii; see page 411. In this Journal and in the Vermont 

 ^Report the letters are followed by letters to M. Barrande from Logan and from 

 Hall; also in the Boston Proceedings, vol. vii, and also vol. viii, 2:-59, by remarks 

 of Mr. Marcou, giving his view of the bearings of the facts on the Taconic sys- 

 tem of Emmons, with some additional facts. .Barrande's Memoir referred to 

 above is entitled, " Documents anciens et nouveaux sur la Fauna primordiale et le 

 Systeme Taconique en Amcrique," and was presented to the Geological Societv of 

 Prance, Nov., 1860, and Feb., 1861. 



Barrande's letters appeared also in the Canada Nat. and Geol. for 1861. The 

 facts show that some person connected with the Geological Survey of Canada is 

 accountable for the "omission" above referred to. Mr. Marcou's paper of 1884 

 gave the editors of this Journal their first knowledge of it. 



