375 



Prof. Emmons has always regarded these black slates of Geor- 

 gia as part of his Taconic system, and more, he refers them to 

 the base of the upper division of the Taconic rocks (see " Amer- 

 ican Geology,^' part II. p. 49). The strata are dislocated and 

 upheaved at Georgia, and as far as my knowledge of the geology 

 of the vicinity of Burlington, Isle La Motte, Chazy, and Rouse's 

 Point extends, acquired in an ex[)loration of a few days in 1849, 

 I am far from agreeing with the statement made by Messrs. Logan 

 and Hall that the strata of Georgia are of the age of the Hudson 

 River group. Mr. Emmons, I think, rightly refers them to the 

 Taconic system, and the discovery of the three primordial trilobites 

 confirms the view arrived at by him only through their strati- 

 graphical and lithological characters. 



In another letter, dated Paris, 14th August, 1860, M. Barrande 

 says : — 



" You will easily perceive the interest and importance of the question, 

 even if it were only raised on account of the three Oleni of Georgia ; 

 but it takes in now a much wider field, owing to a letter I have just 

 received from Mr. Billings, official paleontologist of the Geological Sur- 

 vey of Canada, who informs me that he has found lately, in the schists 

 and limestones near Quebec, considered as being the prolongation of 

 those in question in Vermont, nearly one hundred species, almost all 

 new. Twenty-six of these come from a white limestone, and seem to 

 him to be the true representatives of the Primordial fauna, and he cites 

 among them Conocephcdites, Ai'ionellus, Dikelloceplialus, etc., that is, 

 very characteristic forms of this fauna. 



" In another limestone, which is gray, he finds thirty-nine species, all 

 difierent from the first, and representing, on the contrary, the most dis- 

 tinct types of the second fauna. Finally, the black schists furnish him 

 with Grapiolites, Lingulce, etc., etc., fossils which at first sight cannot 

 determine a horizon, because they are found upon several Silurian 

 horizons. 



" While waiting for the very obscure stratigraphical relations to be 

 disentangled, and without engaging in any manner Mr. Billings, who 

 should preserve the independence of his opinion, I may yet express to 

 you my view wholly personal, and of which at this moment I take the 

 entire responsibility. I think, then, that this region of schists and lime- 

 stones of Vermont, in other words the Taconic sijstem, will reproduce 

 in America that which took place in England as to the Malvern Hills 

 and in Spain for the Cantabrian chain, — that is to say, the Primordial 



