(JKAITOLITES OF NeW YORK. TART 1 731 



Climacograptus? antennarius Hall (sp.) 



Plate 16, fl^ures 21-26 



Climacograptus antennarius Hall. Geol. Sur. Can. decade 2. 1865. p.ll2, 



pl.l3, fig.11-13 

 Diplograpsus antennarius Nicholson. Quar. Jour. Geol. Soc. 1868. 



24:139 

 Cryptograptus? antennarius Lapworth. Ann. and Mag, Nat. Hist, ser 5. 



1880. 5:174 

 Cryptograptus antennarius Gurley. Jour. Geol. 1896. 4:299 

 Cryptograptus? antennarius Elles. Quar. Jour. Geol. Soc. 1898. 



54:519ff, fig.3l 

 Climacograptus antennarius Roemer & Freeh. Lethaea palaeozoiea. 1897. 



1:611 

 Cryptograptus antennarius Ruedemann. N. Y. State Paleontol. An. Rep't. 



1902. p.571 



Description. Rhabdosorae medium sized (about 20 mm), of nearly 

 uniform width (2.7 to 3.5 mm) ; provided with a stout sicular spine and 

 two long, slightly curved, rigid lateral spines, diverging at an angle of 

 100° to 110° and attaining a length of about 5 mm. Sicula not distinctly 

 observed." Thecae closely arranged (9 to 11 in 1 mm) ; parallel to the axis 

 of the rhabdosome ; apertures transverse oval incisions. Nemacaulus stout 

 and straight, its proximal extension relatively very long, measuring 18 mm 

 in one instance. 



Position and localities. Common in the horizon with Dip log rapt us 

 dentatus, exposed at the dam of the Deep kill. Hall's types came 

 from the Quebec group at Point Levis (upper horizon). Nicholson and 

 Elles have recognized this form among the Skiddaw graptolites, and record 

 it as occurring at various places in the Upper Skiddaw slates ; Gurley lists 

 it also among the Arkansas graptolites. 



Memarhs. The synonymy shows that this small form, which by its 

 outline and distal spines appears so well characterized, presents indeed, con- 

 siderable! difficulties to a determination of its generic relations. While Hall 

 desci'ibed it as a Climacograptus, it has subsequently been I'eferred to 

 Dii)lo!L:'r;iptus by Nicholson, to Cryptogi'aptus by Lapwoi'tli, (rurley and 



