GRAPTOLITES OF NEW YORK, PART 1 631 



ciud Logaiiograptus denotes the preceding stage where the unlimited for- 

 mation of branches in Clonograptus has become normally restricted to those 

 of four orders only. Normally a J^oganograptus has hence 16 branches; 

 but imperfect fixation to branches of four orders on one hand, and incipient 

 reduction to lovvei' orders of branches on the other cause considerable 

 variation in the number of branches. Thus in our material of L. logani 

 there occur specimens with as many as 25 branches, there still being present 

 branches of the fifth order, ^vhile, on the other hand, Elles and Wood 

 mention specimens of the same species with but six branches where only one 

 fourth dichotomy has taken place. 



Loganograptus logani Hall 



Plate 9, figures 3-6 



Graptolithus logani Hall. Geol. Sur. Can. Kep't. for 1857. 1858. p.ll5 

 Graptolitbus logani Hall. Canadian Organic Remains, decade 2. 1865. p.lOO, 



pl.9, fig.1-9; pl.ll,fig.7 

 Loganograptus logani Hall. N. Y. State Cab. Nat. Hist. 20th An. Rep't. 



186T. p.226 

 Dicliog rapt lis logani Nicholson. Quar. Jour. Geol. Soc. 1868. 24:128 

 Loganograptus logani Nicholson. Monogr. Brit. Grapt. 1872. ptl, p.l09, 



fig.52c, p.llO 

 Graptolites (Didymograpsus) logani McCoy. Geol. Sur. Victoria. 



Prodr. Pal. Yietoria, decade 1. 1871. p.l9 

 ?Loganograptus logani Etheridge jr. Ann. and Mag. Nat. Hist. ser. 4. 1874-. 



14:4, pl.3, fig.l2 

 Non Loganograptus logani Etheridge jr. Ihid. pl.3, fig.ll ( = Gonio- 



g rapt us thuredui) 

 Dichograptns logani Herrmann. Geol. Mag. Dec. 3, 1886. 3:24 

 Cf. Dichograptus kjerulfi Herrmann. Geol. Mag. ser. 3. 1886. 3:22, 23, 



%.8 

 Loganograptus logani Ami. Geol. Sur. Can, Rep't. ser. 2. 1889. v.3, pt2, 



p.ll7k 

 Dichograptus logani Matthew. Roy. Soc. Can. Proc. and Trans. 1893. 



11:114 

 Loganograptus logani Gurley. Jour. Geol. 1896. 4:294 



