THE GRAPTOLITE (LEVIS) FACIES OF THE BEEKMAN- 

 TOWN FORMATION IN RENSSELAER COUNTY N. Y. 



BY RUDOLF RUEDEiMANN 



La masse schisteuse de la vallee de V Hudson, renfermant de nom- 

 breux graptoiites, V existence de ces fossiles sur Vhorizon de la faune 

 primordiale serait un fait particulier au continent americain et digne 

 de la plus grande attention. II resterait a etablir les relations, soit 

 paleontologiques, soit stratigraphiques, entre ces graptoiites de la 

 vallee de I'Hudson et ceux de la Pointe Levis, pres Quebec. 



Barrande. 1862 



DESCRIPTION OF THE EXPOSURE 



The section described in this paper is exposed along the Deep 

 kill, a small eastern tributary of the Hudson river, and begins 

 about a quarter of a mile east of the small settlement known 

 as Grant Hollow in the northwestern part of Rensselaer county. 



a In ascending the Deep kill valley from Grant Hollow, the 

 first exposure is a small outcrop in the south bank of a few 

 feet of deep black mudstone giving conclioidal fracture. This 

 rock has furnished no fossils. Another outcrop, where are 

 exposed somewhat contorted dark gray, sandy, thinly bedded 

 shales with a few intercalations of argillaceous sandstone, is 

 30 feet farther up. These strata also proved to be barren of 

 organisms. 



The continuous section begins 700 feet farther east, on the 

 north side of the creek. The beds of this exposure are, in con- 

 trast to those met with farther up and down the creek, free from 

 flexures and dip uniformly N 116° E at an angle of 24°. It is 

 apparent that the extremely heavy bedded, hard silicious beds 

 and the limestones prevailing in this section protected the 

 shales from being thrown into the many small, closely packed 

 folds so characteristic of the softer and more pliable terranes 

 of the region. There is no cleavage in these beds; and the 

 slickensides, which often run subparallel to the bedding planes 

 and obliterate or at least distort all organic remains in so many 

 outcrops of the Trenton, Utica and Lorraine shales in the Hud- 

 son river region, are frequent only where the heavy quartzose 

 banks have slipped along the thin shale partings. To the 

 absence of these antagonists of the paleontologist the beautiful 



