126 JULES MARCOU ON THE TACONIC OF GEORGIA 



"Vermont and Canada," with a " comparative tabular section," Cambridge, Mr. Marcon 

 describes, at p. 5, the Georgia slates on the fai-m of Di-. Hall, east of Swanton, and points 

 out two lenticular masses of very hard blue and whitish limestone, inclosed in the slates 

 and sandstones. The fossils found in the limestone and in the slates are: Olenellus 

 TJiomjJsoni, 01. Vermontana,' Conoceplialites Teucer, Oholella cingulata, OrtMsina fer- 

 tinata and Camerella antiquata. 



It is in this paper that the announcement is made of the existence of lenticulai" masses 

 of limestone, more or less glolndar, distributed without any regular order in all the dif- 

 ferent divisions and groups of the Taconic system, in Vermont as well as in Canada; 

 and also that at Pointe-Levis and at Phillipsburgh are found in some of the lenticular 

 masses, Precursory Center of Creation, or Colonies of the Second Fauna inclosed in 

 strata containing the Primordial fauna; a fact not recorded until then in America and 

 showing that here as well as in Bohemia we have forerunners and jJi'ophetic ty]}es, sjie- 

 cific as well as generic, making their appearance in a period anterior to the one in 

 which they have obtained their full development. Mr. Marcou calls these lenticular 

 masses, Lentictda,r precursors, in order to distinguish them from the lenticular masses 

 containing only primordial fossils, as are those of Dr. Hall's farm at Swanton, which he 

 calls Lenticular j^rimor dials. 



1867. Prof. C. H. Hitchcock, in a Geological Map of New HampsTiire and Ver- 

 mont, does not use the name Georgia slates nor Georgia formation, as he did in the 

 " Geology of Vermont," in 1862, and in the explanation of colors, we have the followmg 

 classification, in ascending order. 



Laurentian. 



Montalban or Atlantic. 



Huronian. 



Kearsarge and andalusite groi;p. 



Rockingham and ferruginous schists. 



Cambrian clay slates. 



Cambrian (Potsdam) . 

 Coos group and calciferous mica- 

 schist. 

 Cambro-silurian. 

 Taconic schist. 

 Helderberff. 



Another nomenclature somewhat different from the one given in his geological map of 

 Vermont of 1861, but in Avhich he maintains the Taconic as Upper Silurian. The 

 township of Georgia, on the map of 1867, is colored as Potsdam and Cambro-silurian. 



1867 (Dec). Pev. John B. Periy, in a paper entitled: "Queries on the red sandstone 

 of Vermont and its relations to the other rocks," read and published, in the Proceed. 

 Boston Soc. Nat. History, December 18, 1867, Vol. xi, uses the name Georgia slates, 

 with the same meaning that Mr. Marcon does, giving also the same list of fossils (see 

 Separate, ]). 9, 1868). 



1880 (Nov.). Mr. Marcou publishes in his paper, "Sur les colonies dans les roches 

 Taconiques des bords du lac Champlain {^Bulletin Soc. geol. Prance, .3® serie, tome ix, p. 

 18, Paris), a detailed description of Georgia, with sections in the text and on Plate ii, 

 and a geological map of all the area round Georgia, Parker's farm and St. Albans. He 

 uses the name Schistes de Georgia and mentions two new fossils, a brachiopod and a 

 Dikelocephalus. 



1884 (Feb.). The Bulletin American Museum of Natural History, j!*^ew York, Vol. 

 I, Xo. 5, contains two articles: "Notice of some new species of primordial fossils, etc.," 

 by R. P. Whitfield; and "Geological sections across I^ew Hampshire and Vermont," 



