ClfAI'TOLITES OF NEW YORK, PART 1 



TOT 



Cf . P li }■ 1 1 g r a p t u s i 1 i e i f o 1 i u s var. g r a n d i s Ellcs & Wood. Monogr. Brit. 



Grapt. pt 1. Pal. See. vol. for 1902. p.l02, pl.l3, %.8 

 Pliyllograptus ilicifolius Ruederaaun. N. Y. State PaleoBtol. An. Rep't. 



1902. p.554, 556. 



Descri^^tion. Rliabdosome consisting of four branches, mostly broadly 

 semioval, which are joined at right angles by their longitudinal axes so as 

 to form two intersecting ovals. The rhabdosome attains a maximum length 

 of 19.5 mm and a width of 11.3 mm; the dimensions of average specimens 

 are however smaller by one fourth. Character and length of sicula not ascer- 

 tained ; sicnlar end provided with a rather long (8 mm) 

 spine. The thecae are in contact throughout their 

 length, number, in the majority of the specimens, 12 in 

 10 mm, with variations to 11 and 18; they are much 

 curved; first ascending near the sicular end, then 

 curving outward and downward, this curvature decreas- 

 ing gradually toward the center, 

 where the thecae are but slightly 

 bent and placed approximately 



horizontally ; toward the antisicular portion of the 

 rhabdosome they become more and more directed 

 upward, till at the antisicular end they run subparallel 

 to the axis of the rhabdosome. The apertures are 

 W^^Z,^^ slightly concave ; oblique in the sicular portion and 



1^^ --:;^ vertical on the axis of the thecae in the central and 



antisicular portions ; their lower margins are extended 

 into short concave tongues [fig.95] Avliich in the 

 laterally compressed rhabdosomes appear as slender 

 mucros [fig.96j. 



Position, (Old localities. Very common and typical in graptolite bed 2 

 (Tetragraptus horizon) ; rare in graptolite bed 1, belonging to the same 

 horizon and not observed in typical specimens in the highest horizon of 

 the Deep kill section. In the beds ^vith Didymograptus bifidus 



^ 



<^ 



A 



Fig. 95 P h y 1 1 o g- r a p t \i s 

 ilicifolius Hall. Mai-giu- 

 al portion showing- thecal 

 apertures and mucros. Deep 

 kill. x8 



Fig. 96 Phyllograptus 

 ilicifolius Hall. Enlarge- 

 ment of a part of a rhabdo- 

 some. Deep kill. x6 



