GRAPTOLITES OF NEW YORK, PART 1 



611 



otherwise disturbed, and the terms Lower and Middle Arenig should be 

 exchanged. 



If, however, the species recorded by Gurley from the Main Point Levis 

 zone which corresponds to the Tetragraptus beds of the Deep kill section is 

 identical with our form, the latter would range from the Tetragraptus horizon 

 to that with Diplograptus dentatus. 



Remarhs. This form, in some of its distal parts, agrees 

 so closely with the description and figure of Dictyograp- 

 tus (Desmograptus) cancel latus, that a separa- 

 tion from this species does not appear to be justified. The 

 only apparent difference is the greater width of the branches 

 in the Welsh specimen, a feature which in view of the varia- 

 bility of the thickness of the branches in the Deep kill speci- 

 mens can not be considered as of diagnostic value. The figure 

 of the type specimen which is a representation of a more 

 distal part shows also the presence of more elongate meshes 

 in a basal direction. 



Gurley described a form from the Beekmantown shales of Point Levis 

 as D. macrodictyum, which is said to differ from D. cancellatus 

 by the straight branches, the greatly elongate meshes and the generally 

 stouter structure. As the specimens figured here exhibit these same 

 differences between basal and distal parts of the rhabdosome, it is probable 

 that his type is also referable to this species and belongs only to a more 

 basal portion than the original. Since Dr Gurley did not figure his species, 

 which was found in the Main Point Levis zone, a definite reference is 

 excluded at present. 



Desmograptus intricatus sp. nov. 



Plate 3, figures 1-4 



Dictyonema (Desmograptus) sp. nov. Ruedemann. N. Y. State Paleontol. 

 An. Rep't. 1902. p.570 



Description. Rhabdosome infundibuliform ; rapidly widening by oft 



lepeated bifurcations of the branches, attaining a length and width of 



Fig. 82 Desmo- 

 graptus Intrl- 

 catus sp. nov. En- 

 largement of part of 

 the specimen repro- 

 duced on pl.3, ng.3. 

 Deep kill. x6 



