240 



part of our pamphlet, under the altered and false title * of, On the Pri- 

 mordial Fauna and the Taconic system of Emmons, in a letter to Prof. 

 Bronn of Heidelberg. 



While these publications were in progress in America, M. Barrande, 

 in the Bulletin de la Societe Ge'ologique de France, Vol. xviii. p. 203, 

 at the meetings of Nov., 1860, and Feb., 1861, gave a long, elaborate, 

 and impartial memoir, entitled, " Documents anciens et nouveaux sur 

 la faune primordiale et le systeme Taconique en Amerique, with two 

 plates ; in which he gives at length the numerous, sagacious, and 

 profound observations of Dr. Emmons on the Taconic system, so long 

 kept in the background. 



Professor Agassiz, who has contributed much to the enlargement of 

 our views and notions as to the great value of paleontological charac- 

 ters for the determination of the relative age of strata, desirous to assist 

 in the elucidation of the difficulty, signalized with snch a masterly 

 hand by M. Barrande, sent me to Vermont and Canada to collect all 

 the specimens of fossils, and all the facts I could reach, for the benefit 

 of his Museum of Comparative Zoology. I give below a very sum- 

 mary resume of what I have seen, reserving all the detailed sections, 

 new fossils, and geological maps, for a longer memoir now in prepa- 

 ration. 



I must begin by the statement that the Taconic system of Dr. 

 Emmons is the true base of the sedimentary strata in North America, 

 and that I agree in the main with all the observations, sections, and 

 descriptions of fossils of Dr. Emmons, who, in establishing the founda- 

 tion-stone of the pillar of American Stratigraphy, has given in his 

 different memoirs on the Taconic system the most difficult and impor- 

 tant geological works which have ever been produced on this side of 

 the Atlantic. 



My researches were principally directed toward the upper part of 

 the Taconic series and the Lower Silurian, and I give a tabular view, 

 showing the succession of groups of strata. This I was able to make 

 out for the vicinity of Georgia, St. Albans, Swanton, Highgate-Springs, 

 and Phillipsburgh, on the north-eastern shore of Lake Champlain. 



Lorraine Shales. — This group, which has been also called Pulaski 

 Shales and Hudson River GroujJ, docs not occur at Snake Mountain, 

 nor in the vicinity of St. Albans, Georgia, Swanton, and Highgate. 

 Indeed, I did not find a single trace of this group anywhere on the 

 main land of Vermont, and I only saw it on the peninsula of Alburgh, 

 between Missisquoi Bay and Rouse's Point, where it presents the rocks 



* I regret to say that this is the second instance since 1858 in which the editors of 

 Silliman's Journal liave not only appropriated letters belonging to me, but attrib- 

 uted them to persons who have had nothing whatever to do with them. 



