160 Tertiary. 



the great valleys. lu the Champlain valley, it is nearly north and 

 south; and in the St. Lawrence valley, northeast and southwest. The 

 marine Tertiary of Champlain, though deposited in quiet waters, al- 

 ways overlies the scored and grooved surfaces. The bowlders succeed 

 this Tertiary or are mixed with it. It is mineralogically composed in as- 

 cending order, of first, a stiff blue clay; second, a 3'ellowish brown 

 clay; and third, a yellowish brown sand. The second owes its color 

 to weathering rather than to any important difference in its composi- 

 tion from the lower cla3\ Sand begins to appear in the yellowish clay, 

 and increases gradually until it predominates, and finally becomes a 

 pure siliceous sand. No fossils had then been discovered in the clay, 

 but in the clay and sand and upper part of the group fossils are found 

 as if in their native habitat, exceedingly frail, preserving their mai'k- 

 ings and edges entire, forbidding the idea that the^' could have been 

 drifted into their present position. In protected places, as at Port 

 Kent and Beauport, the thickness of the group is about 100 feet. In 

 unprotected places, the larger part of the group has been swept away. 



Commencing at Whitehall, at the head of Lake Chami)lain, it may 

 ■be traced continuously not only the entire length of the lake, but also 

 to Quebec and far toward the Gulf of St. Lawrence. It lines the St. 

 Lawrence river as far as Ogdensburg. And from Whitehall south it 

 lines the Hudson river for a long distance. The Albany clay belongs 

 to this group, and is therefore one of the most recent of our mai'ine 

 formations. 



Mr. Conrad* described, from the Miocene at Calvert Cliffs, Mary- 

 land, Venus latilirata., Cytherea subnasuta, Luciiia foremani., L. sub- 

 planata, Cardium leptopleura, Astarte varians, A. exaUata, Lima 

 papyria, Area subrosfrata, Pleurotoma marylandicum, P. bellicrena- 

 tum, Trochus peralveatus, Scalaria pachypleura. Solarium trilineatum, 

 now Architectonica trilineata^ Infundibulum perarmatum, Fissurella 

 marylandica, DisjJoUea ramosa, Cancellaria biplicifera., C. engonata, 

 Bonellia lineata, Twritella indenta, T.exaltata, T. perlaqxteata, Mar- 

 gineUa perexigua. And also Astrea marylandica, incrusting Pecten 

 madisonius on James river, Virginia; A. bella, h-om Newbern, North 

 Carolina; Cardium nicolletti, now Protocardia nicolletti, from the 

 Lower Tertiary or Jackson Group, on the Washita river, Monroe 

 county, Louisiana; and Fusus pachyleurus, from the Lower Tertiar}" of 

 Alabama. 



Edmund Raveuelf described, from a Pliocene calcareous deposit on 



* Joui-. Acad. Nat. Sci., vol. viii., pt 2. f Ibid. 



