New York State Museum 



HUDSON RIVER BEDS NEAR ALBANY 



AND THEIR 



TAXONOMIC EQUIVALENTS 



INTRODUCTION! 



The study ol a rich graptolite fauna from the vicinity of the 

 city of Hudson, Columbia co., identical with the Nonnans kill 

 fauna of Kenwood, Albany co., made known by the late Prof. 

 Hall, impressed the writer with the great uncertainty still prevail- 

 ing among geologists as to the age of these shales and with the 

 wide differences in their stratigraphic assignments by various 

 writers. To illustrate this condition the most important of these 

 differing views may be cited. While Hall finally placed the grap- 

 tolite-bearing shales of Normans kill above the Utica shale and in 

 the Hudson river beds> asserting their homotaxy with the Lor- 

 raine beds, Whitfield and Walcott have considered them a part of 

 the Utica shale formation. Lapworth and Gurley assign them to 

 the Trenton stage, and Ami is inclined to regard) them as lying 

 below the Trenton and above Chazy limestone. Freeh recently 

 cites graptolites of this zone as from the " Utica shale of Nor- 

 mans kill.'^ 



Such an apparent inability to correlate properly a terrane with 

 «uch a rich fauna would seem inconceivable, specially so in a 

 Btate which, by the labors of Prof. Hall and of his many follawew, 

 has furnished the standard scale of formations for all America^ 

 were it not for the indescribably folded, tilted and crushed con- 

 dition of the beds, the one-sided character of the fauna, and the 

 distribution of the graptolites in thin bands in the otherwise 

 utterly barren, huge mass of shales and sandstones, which, practi- 



'This paper was submitted Ap. 1, 1900, to the Boston society of natural 

 history in competition for the Walker prize, and a synopsis of the sam* 

 read before the American association for the advancement of science Junt 

 16, 1900. 



