526 NEW YORK STATE MUSEUM 



PLATE 19 



Dicellograptus sextans (Hall) 



Page 306 



1 Group of typical specimens 



Normanskill shale, Glenmont, N. Y. 



Dicellograptus sextans var. perexilis now 



Page 310 



2 Type specimen (holotype). 



Normanskill shale, Mt Moreno near Hudson, X. Y. 



Dicellograptus smithi sp. now 



Page 313 



3, 4 Groups of associated specimens showing the typical expression of 

 the species ; the specimens reproduced in figure 4 being selected 

 as the types 



5, 6 Specimens with crossing branches 



Trenton shaly limestone, Pratt's Ferry, Bibb co., Ala. 



Dicellograptus gurleyi Lapworth 



Page 303 



7 Specimen showing a double crossing of the stipes 



Normanskill shale, Glenmont, N. Y. 

 8, 9 Specimens with the typical expression of the species 



Normanskill shale, Glenmont, N. Y. 

 10 Specimen from the type locality (topotype) 

 Normanskill shale, Stockport, N. Y. 



All the figures are drawn in natural size. The originals of figures 

 1, 2, 7-9 are in the New York State Museum; those of figures 

 3-6 in the collection of the Geological Survey of Alabama ; that 

 of figure 10 in the National Museum. 



