GRAPTOLITES OF NEW YORK, FART 1 



581 



Dendrograptus (?) succulentus sp. nov. 



Plate 4, figures 1-4 



Deudrograptus sp. nov. Kuedemann. N. Y. State Paleontol. An. Rep't. 1902. 

 p.570 



Description. Rhabdosome very robust in its basal parts, braucliiug 

 very irregularly, often so frequently that the successive branches are 

 nearl}' in contact ; angles of branching very differ- 

 ent in the basal parts ; branches abruptly break- 

 ing up into pendent tufts of frequently dividing 

 branchlets. Thecae not projecting ; thecal aper- 

 tures small, circular depressions, ^vhicll iu the basal 

 parts are found apparently irregularly distributed 

 around the entire circumference of the branches, 

 Avhile on the thin bi'anches a serial arrangement is 

 indicated. On the latter they number 8 to 10 in 

 10 mm. AVhere the external periderm of the 

 branches has become exfoliated, their composition 

 of fine tortuous thecal tubes is observable. 



Position and localities. Common at the Deep kill in the shale of the 

 horizon ^vith Diplograptusdentatus. 



Hemarlcs. This species is easily distinguished from any other species 

 of Dendrograptus known to the Avriter from the American Lower Siluric. 

 D . serpens Hopkinson and Lap worth from the lower Llandeilo of 

 Abereiddy bay in Wales [1875, p.665] is also characterized by robust 

 basal branches and pendent terminal tufts of branchlets. From that younger 

 species the Deep kill form is readily distinguished by its less diffuse habit, 

 much closer branching and more rigid and ascending character of the 

 branches ; and the much more rapid decrease in thickness of the more distal 

 branches. D . e r e c t u s Hall, from the Point Levis Tetragraptus shales, 

 of which only the basal part is known, possesses also ascending branches; 

 the latter are however neither so closely arranged nor so thick and robust 

 as in D . s u c c u 1 e n t u s „ 



Fig. 16 Dendrograptus (?) 

 succulentus sp. nov. Frag- 

 ment which shows the composition 

 of the branches of numerous tubes. 

 Deep kill. x3.75 



