OT^VPTOLITES ()!•' NEW YOriK, PART 1 719 



being united in the center by a funicle and a central disk [p,528], and that 

 from the latter originate the gonangia in which new siculae are produced ; 

 and Wiman has sho^\•n that the apparent biserial arrangement of the thecae is 

 produced by one series, the thecae budding alternately on opposite sides 

 [p.538]. 



Diplograptus dentatus Brongniart sp. 



Plate 17, figures 10-13 



Fucoides den tat ns Brougniart. Hist. Veget. Foss. 1828. l:70ff, pl.O, 



iig.9-12 

 Graptolithus pristiniformis Hall. Geol. Sur. Can. Eep't. 1857. 



p,133 

 Diplograptus pristiniformis Hall. Geol. Sur. Can. . decade 2. 1865. 



p.llOfI, pl.l3, fig.15-17 

 Diplograptus pristiniformis Nicholson. Quar. Jour. Geol. Soc. 1868. 



24:140, pi. 5, fig.l4, 15 

 Diplograptus dentatus Hopkinson & Lapworth. Ibid. 1875. 31:656fF, pl.34, 



fig.5a^k 

 Diplograptus dentatus Ami; Geol. Sur. Can. Rep't, ser.2. 1889. v.3, pt 2, 



p.ll7k 

 Diplograptus dentatus Gurley. Jour. Geol. 1896. 4: 298 

 Diplograptus dentatus Elles. Quar. Jour. Geol. Soc. 1898. 54 :517fP 

 Diplograptus dentatus Ruedemann. N. Y. State Paleontol. An. Rep't. 1902. 



p. 570 



This type, which is veiy common in the graptolite beds at the dam in 

 the Deep kill section and at Mt Moreno, not only presents a great variety 

 of ap]3earances, some of Avhich are I'epresented l^y the camera tracings but also 

 considerable variations in its dimensions. 



Description. , The rhabdosoraes are as a rule narrow, attaining their full 

 width (1.8 to 2.1 mm) at an early stage of their growth, and maintaining this 

 throughout. Perfect specimens attaining a length of 45 ram have been 

 observed, but fragments indicate that they grew still beyond that size. The 

 thecae are closel}" ai-ranged ; they number 10 in 10 mm in most specimens, but 

 in the earliest parts of a few niiml)er 14 to Ifi and in the later portions of 



