534 NEW Y0RK STATE MUSEUM 



PLATE 23 



Dicranograptus ramosus Hall 



St-e plate 21, figures 6, 7 

 Page 325 



i Specimen with long biserial portion 



Normanskill shale, Mt Moreno, N. Y. 



Dicranograptus spinifer Lapworth 



Page 330 



2 Group of specimens of a late mutation 



Utica shale, Oxtungo creek, N. Y. 



3 Typical specimen 



Normanskill shale, Glenmont, N. Y, 



Dicranograptus spinifer var. geniculatus no v. 



Page 333 



4 Specimen with extreme geniculation of the uniserial stipes, and strongly 



spinose biserial part of rhabdosome (holotype) 

 5, 6 Specimens with less geniculation, and broad biserial parts 

 Normanskill shale, Glenmont, N. Y. 



Dicranograptus furcatus (Hall) 



Page 334 



7 Group of specimens showing the common appearance 



Normanskill shale, Kenwood, N. Y. 



Dicranograptus furcatus var. exilis now 



Page 337 



8 Type specimen (holotype). Too v/ide in the reproduction 



Normanskill shale, Kenwood, N. Y, 



