246 



P. Vermontana, Obolella cingulata, Ortliisina festinata, Camerella anti- 

 quata, Conoceplicdites Ceucer, and Chrondites^ a mile and a half east of 

 the village of Swanton ; and Mr. James Richardson has collected 

 specimens of the same Paradoxides farther east, at L'anse an Loup, 

 on the north shore of the straits of Belle Isle, Labrador ; (see Neio 

 Species of Loioer Silurian Fossils, hj E. Billings. Montreal, Nov., 1861). 



Saint Albans Group. — The road between St. Albans and Georgia, 

 and thence from Georgia to Mr. Parker's house, lies all the ^vay on 

 green, brown and reddish slates, containing now and then large lenti- 

 cular masses of very hard, whitish-gray limestone. Thickness, be- 

 tween tAventy-five hundred and three thousand feet. I did not find 

 any fossils, although I heard of one specimen of Trilobite picked up 

 behind the town of St. Albans by an inhabitant, nor was I able to 

 see that specimen. The reddish slates, which are not well developed 

 in Vermont, as regards the red color of the rocks, lie at the base of 

 the upper Taconic strata. They are worthy of notice, as containing 

 the veins of sulphuret and copper pyrites of the Acton mines, in 

 Canada, and the Bruce and Wallace mines of Lake Huron. 



Below the St. Albans group are quartzite, conglomerates, talcose 

 slates, clay slates, mica-schist, and gneiss, with intercalation of beds 

 and lenticular masses of crystalline limestone, resting on the unstrati- 

 fied and oldest crystalline rocks of the White Mountains, and compos- 

 ing the Loicer Taconic system. Dr. Emmons did not put in his Lower 

 Taconic the mica-schist and gneiss, which form the central and east- 

 ern part of Vermont, but on a close examination of the subject in the 

 vicinity of Eutland, Bolton, and Island Pond, I have come to the con- 

 clusion that these rocks have a stratified and sedimentary origin, and 

 that they are the base of the Taconic system. All the strata of the 

 Lower Taconic system are more or less metamorphic, especially at the 

 base ; — the metamorphism produced by the action of mineral springs 

 during the deposits, together with pressure caused by the divers dislo- 

 cations to which they were afterward submitted. The Lower Taconic 

 is at least ten thousand feet thick, making fifteen thousand feet the 

 minimum for the Taconic system of Vermont. It is difficult to give 

 the thickness of the strata with any exactness, as the Green Mountains 

 present a fan-like structure, similar to that of the Alps and Pyrenees. 



Twelve years after the discovery and description of the Taconic 

 system, Mr. Logan, having met with some of the Taconic rocks on the 

 southern edge of the Laurentine Mountains, between the Saguenay 

 River and the Bruce mine on Lake Huron, and overlooking entirely 

 the researches of Dr. Emmons, proposed to introduce into the table of 

 the American strata two new systems, which he called the Laurentian 

 and Huronian systems ; (see Esquisse Geologique du Canada, Paris, 

 1855). The Laurentian system is composed of the Lower Taconic, to 



