296 NEW YORK STATE MUSEUM 



Position and localities. From the beds of New York State I have seen 

 but one slab. This bears six individuals and comes from the Normanskill 

 shale at Kenwood. The species is associated with D i p 1 o g r. f o 1 i- 

 aceus, Climacogr. parvus and Nemagr. e x i 1 i s. A specimen 

 with like characteristic curvature, small width of rhabdosome and form of 

 thecae has been observed in the Trenton shales from Alabama, in association 

 with D i p 1 o g r. foliaceus van alabamensis and Dicellogr. 

 s m i t h i. 



Remarks. The only congener of which one could be reminded by the 

 form of this graptolite, is D. elegans Carr., but that species has quite 

 different thecae and greater width of the branches. The thecae of D . 

 mensurans indicate that it is one of the primitive members of the L r enus 

 and probably the most primitive occurring in the New York beds. It rep- 

 resents here the first of the subdivisions of the Dicellograpti, discerned by 

 Elles and Wood, but differs markedly from the other species of this group 

 by the slenderness of its thecae. 



Dicellograptus divaricatus ( Hall) 



Plate 18, figures 3, 4 



Graptolithus divaricatus Hall. Pal. N. Y. 1859. 3: 513, p. 5 14, fig. 1-4 

 Graptolithus divaricatus Hall. N. Y. State Cab. Nat. Hist. 13th An. Rep't. 



i860, p. 58, fig. 

 Graptolithus divaricatus Hall. Can. Org. Rem. Dec. 2, 1865. p. 14, fig. 19 

 Graptolithus (D i c r an o gr a p t u s) divaricatus Hall. X. Y. State Cab. Nat. 



Hist. 20th An. Rep't. 1868. p. 180, fig. 20 

 D i d y m o g r a p t u s divaricatus Nicholson. Ann. & Mag. Nat. Hist. 1868. 



5:351 ; pi. 7, fig. 4 

 Dicellograptus divaricatus Hopkinson. Geol. Mag. 187 1. 8:25; pi. r, fig. 4 

 Didymograptus divaricatus Nicholson. Monogr. Brit. Grapt. 1872. p 55, 



62, fig. 

 Dicellograptus divaricatus Hopkinson & Lapworth. Quar. Jour. Geol. Soc. 



1875- 3 T : 6 54; pi. 34, fig- .Vb b 

 Dicellograptus divaricatus Lapworth. Cat. West. Scott. Foss. 187(1. p.5 ; 



pi. 4, fig. 86 

 Dicellograptus moffatensis var. divaricatus Lapworth. Belfast Nat. Field 



Club. Rep't & Proc. v. t, pi 4. 1877. apx. p. 141, pi. 7. fig. 10 



