GRAPTOLITES OF NEW YORK, PART 2 2 J J 



In general aspect the mode of branching of Nemagraptus gra- 

 cilis is truly monopodial or lateral, the slight diversion of the stolonal 

 thecae from the axial direction ol the mother thecae after their becoming' 

 free is however an indication of a trace of a former dichotomous mode of 

 branching. 



The genus is here restricted to the Normanskill shale where it occurs 

 in two species with numerous varieties, viz : 



Nemagraptus gracilis (Ifa//) var. approximates nobis 



var. surcularis (Ha/I) Nemagraptus exilis Lapworth 



var. crassicaulis Gurley var. linearis nobis 

 var. distans nobis 



Nemagraptus gracilis (Hall) 



Plate 16, figures 1-5 



Graptolithus gracilis Hall. Pal. N. Y. 1847. 1 : 274; pi. 74, fig. 6a-d 

 Rastrites barrandi Harkness. Geol. Soc. Quar. Jour. 1855. 11:475 

 Nemagrapsus elegans Emmons. Am. Geol. pt 2. 1856. p. 109; pi. 1, fig. 6 

 Graptolithus gracilis Hall. N. Y. State Cab. Nat. Hist. 12th An. Rep't. 1859. 



p. 58, fig. 10 

 Graptolithus gracilis Hall. N. Y. State Cab. Nat. Hist. 13th An. Rep't. i860. 



p. 56, fig. 6, 7 

 Graptolithus gracilis Hall. Pal. N. Y. v. 3. sup. 1859. p.510, fig. 5-7 

 ? Graptolithus gracilis Bailey. Geol. Soc. Quar. Jour. (Dublin). 1862. 9:5; 



pl- 4, fig. 5 

 Graptolithus gracilis Hall. Can. Org. Rem. Dec. 2, 1865. p. 13, 14, fig. 16-18 

 ? Graptolithus gracilis Bailey. Mem. Geol. Sur. Ireland. 1866. Sheet 133, p. 12, 



fig- 3 

 Stcphanograptus gracilis Geinitz. Neues Jahrb. f. Mineral. 1866. p. 124 

 Cladograpsus gracilis Carruthers. Geol. Mag. 1868. 5:130 

 Coenograptus gracilis Hall. N. Y. State Cab. Nat. Hist. 20th An. Rep't. 1868. 



p. 179-80, fig. 17-19 

 Helic ogr ap'su s gracilis Nicholson. Ann. & Mag. Nat, Hist. Ser. 4, v. 2. 1868. 



P-25, fig- 1 

 Coenograptus gracilis Hall. N. Y. State Cab. Nat. Hist. 20th An. Rep't. Rev. ed. 



1870. p. 211, fig. 17-19 

 Coenograptus (H e 1 i c o g r a p t u s) gracilis Nicholson. Monogr. Brit. Grapt. 



1872. p.45, fig. 14 



