39° NEW YORK STATE MUSEUM 



A,j is a mass of rocks exposed for a considerable distance along 

 the shore and consisting of an irregular series of beds of gray brown 

 and bluish black sandy dolomite with thin intercalations of very fos- 

 siliferous limestone. The surfaces of the strata are characteristically 

 marked by an entangled mass of vermiform ridges suggesting 

 fucoids, and by channels, such as are formed on sandy beaches at 

 low tide. These channels are filled with a bluish gray limestone, 

 contrasting with the sandy rocks and choked with fossils, specially 

 orthoceracones, which lie in the longitudinal direction of the chan- 

 nels. The channels run slightly north of east. Systems of large 

 ripple marks extend over some of the rock surfaces. Thickness not 

 obtained. 



A5, rock exposed on north side of Sibley point, exposures begin- 

 ning behind Pacno's barn, where a dolomite bed, 4^ feet thick 

 rests upon A^. This is followed by a cross-bedded impure lime- 

 stone containing numerous cephalopods (nautilicones) and other 

 fossils. 



Ag, 6 feet of a purer, blue limestone, which is irregularly bedded 

 and contains seams of black shale. 



A^, a heavy bed (7 feet) of blue sandy limestone, weathering 

 yellow, exposed at top of bank, at east end of Sibley point. 



A 8, separated by a concealed interval from A^ and consists of 

 about 25 feet of heavy bluish limestone strata, which weather gray, 

 are barren and contain some geodes. This bed ends at the Valcour 

 dock. Strike n. 40 w. ; dip, 15° s. w. 



Section of the Cliazy beds at Valcour in ascending order 



The Chazy beds at Valcour form a low anticline. 



B^, a hard, compact, gray limestone, exposed at water edge, on 

 land of Ezra Day. 2 feet of its top exposed. 



Bo, same rock. 6 inches. 



B3, gray, shaly impure limestone with mud seams ; very fossilifer- 

 ous. I foot 4 inches. 



B4, more crystalline limestone with darker shaly intercalations. 

 I foot 10 inches. Contains numerous small bryozoan reefs and other 

 fossils; also many cephalopods in its upper layer (just north of 

 fence dividing lands of George and Ezra Day). 



B.-,, darker, impure shaly limestone, i foot 6 inches. Contains 

 some large nautiloids. 



Be, a gray shaly limestone. 3 feet, containing a rich fauna (Bol- 

 boporites, Malocystites, brachiopods, trilobites). 



