B40 NEW YORK STATE MUSEUM 



Cryptograptus tricornis', Ga/rruthers sp.(=D. marcidus, Eall) 



Corynoides calicularis, 'Nicholson 



Dawsonia sp. 



Rhombodictyon sp. 



Of these Leptograptus subtenuis, Dicello- 

 graptus intortus,Climacograptufi parvus, 

 Dawsonia and Rhombodictyon are restricted to the 

 Dicellograptus zones, while Cryptograptus tricoirul* 

 passes from the Calciferous into the lower Dicellograptus zone, 

 but not into the Utica or Lorraine beds. This shale is, hence, 

 an unmistakable representative of the Normans kill or lower 

 Dicellograptus beds, and this interesting discovery demonstrates 

 the presence of the Normans kill fauna only a few hundred yards 

 to the east of the middle Trenton fauna. 



Following the section farther up along the Poesten kill, alter- 

 nations of sandstones and black argillaceous shales are first met 

 with, then a four foot conglomerate with black shale as matrix, 

 at the water tower of the wire mill; above this alternations of 

 fissile, black and greenish gray shales and finally, by gradual 

 disappearance of the black shales, only green shales. On the 

 other side of the Poesten kill, just below the picturesque water- 

 falls, specimens of Rhombodictyon were found in a black 

 fihale, intercalated in a green shale, the latter containing great 

 quantities of fragments of algae. These shales extend eastward 

 as far as the great fault which brought up the Cambrian beds 

 against the ^^ Hudson river shales ". 



Station 29. Mount Olympus, Troy 



Another outcrop of graptolite shale was found 2 miles farther 

 north at Mt Olympus, a landmark of North Troy, consisting of a 

 cliff rising some 60 feet above the alluvial plain. 



The deep black, fissile argillaceous shales contain: 



Dldymograptus tenuis, Eall sp. rr 



Dicranograptus ramosus. Hall, r 



Olimacograptu* bioornis, Eall. co 



