708 NEW YORK STATE MUSEUM 



it occurs still sparingly. Hall's types came from the first mentioned horizon. 

 Elles and Wood describe from the Middle Skicldaw slates a varietal form 

 as P . i 1 i c i f o 1 i u s var. g r a n d i s , ^vhich differs from the typical 

 material only hj its much greater size. Some of the largest specimens from 

 the Deep kill approach this major variety in form, but are connected by inter- 

 vening sizes with the uoi'mal specimens. 



Remarks. Hall described this form as broadly oval or ovate. While 

 the majority of the numerous specimens in the Deep kill correspond to this 

 description, there are on one hand extremely broad forms and on the 

 other extremely long and narrow ones [fig.l6, 19], transitional forms leading 

 over to both extremes. 



It is, hence, evident that in this bed at least P. ilicifolius is 

 almost as variable as P . t y p u s in a later horizon. The thecae in the 

 middle part may approach the direction of those of P . a n g u s t i f o 1 i u s , 

 but P . ilicifolius is always readil}- distinguished from that species by 

 the direction of the thecae in the sicular and antisicular portions. 



This form is also easil}^ distinguished from P . t y p u s , which follows 

 it in the Deep kill section, by its more closely arranged thecae and the 

 different chai'acter of the apertures, which here, in the compressed form, 

 are adorned Avitli long, narrow mucros. 



Phyllograptus typus Hall 



Plate 15, ligures 35-37 



Phyllograptus typus Hall. Geol. Sur. Can. Rep't for 1 857. 1858. p.l37 



Phyllograptus typus Billings. Geol. Sur. Can. Pal. Foss. 1865. 1 :366,375 



Phyllograptus typus Hall. Geol. Sur. Can. decade 2. 1865. p.ll9, pl.l5, 

 %.1-12 



o 



Phyllograptus typus Tornquist. Lunds Uni\^ Arsskrift. T. 1, ptiii, 1865. 



p.l6, pl.l, fig.9,10 

 Phyllograptus typus Nicholson. Quar. Jour. Geol. Soc. 1868. 24:133, pl.5, 



fig.l6 

 Phyllograptus folium (His. sp.) var. typus (Hall) McCoy. Geol. Sur. 



Yictoria. Prodr. Pal. Victoria decade 1. 1871:. p.Tf, pl.l, fig.1-4 



