362 



NEW YORK STATE MUSEUM 



Feet 



D, 1 Blue limestone in beds 1 or 2 feet thick, breaking 

 with a flinty fracture, often with considerable dolomitic 

 matter intermixed, giving the weathered surface a rough, 

 curdled appearance ; becoming more and more interstrati- 

 fied with calciferous sandstone in thin layers, which fre- 

 quently weathers to a friable, ocherous rotten stone .... 80 



2 Drab and brown magnesian limestone, containing 

 also toward the middle several beds of tough sandstone. . 75 



3 Sandy limestone in thin beds, weathering on the 

 edges in horizontal ridges one or two inches apart, giving 

 to the escarpments a peculiar, banded appearance. A few 

 thin beds of pure limestone are interstratified with the 

 silicious limestone 120 



4 Blue limestone in thin beds, separated from each 

 other by very thin, tough slaty layers, which protrude on 

 the weathered edges in undulating lines. The limestone 

 often appears to be a conglomerate, the small inclosed 



pebbles being somewhat angular and arenaceous 100 



Thickness of D 375 



E Fine grained, magnesian limestone in beds 1 or 2 

 feet in thickness, weathering drab, yellowish or brown. 

 Occasionally pure limestone layers occur, which are fossil- 

 iferous, and rarely thin layers of slate. Thickness 470 



Total thickness 1800 



Cassin formation. In the upper part of division D and in divi- 



sion E are numerous fossiliferous horizons carrying a rather 

 abundant fauna. These beds are confined to the Champlain valley 

 so far as the immediate region is concerned, and have therefore 

 the same restricted distribution as the following Chazy. In dis- 

 cussing Brainard and Seeley's paper, Professor Whitfield recog- 

 nizes and emphasizes this point and the considerable differences 

 between these upper beds and the ordinary, sparingly fossiliferous 

 character of the normal Beekmantown. He urges the similarity 

 of the fauna to that of the Quebec group of Canada, argues that 

 these beds have more natural affinity with the Chazy than with the 



