GRAPTOLITES OF NEW YORK, PART 1 



601 



ing ii length of 5 cm and more.^ Suspended from a thin, long nema [see 

 description oi genus for discussion of mode of fixation and existence of 

 D . flabelliforme]. 



Branches about . 4 ram wide, subparallel, rigid, bifurcating at long 

 intervals, distant a little more than 1mm (about 18 in 20 mm), con- 

 nected by dissepiments, which are about half as thick as the branches 

 and separated by intervals twice as Avide as the latter, 

 thus forming meshes with the branches which are about 

 twice as long as wide. Thecae (nourishing individuals) 

 disposed on the inside of the branches, forming short, 

 acutely pointed or mucronate processes, numbering about 

 14 to 16 iu 10 mm. Smaller apertures noticeable along 

 the lateral sides of the branches. 



Position and localities. Upper Cambric graptolite 

 shale of Schaghticoke, Rensselaer co. N. Y., in association 

 with S t a u r o g r a p t u s d i c h o t o m u s Emmons 

 ( = C 1 o n o g r a p t u s p r o x i m a t u s Matthew). Very 

 frequent also in black slate at various localities in the 

 slate belt in Washington count}^, N. Y., specially about 

 Granville, as at North Granville, Hillsdale, on Hatch 

 hill, on Marion hill near South Hartford, in several of 

 which localities it is also found associated Avith Staurograptus 

 d i c h o t o m u s . Near South Hartford it occurs also iu a dirty brownish 

 weathering limestone. There is little doubt that its distribution extends 

 northward through Vermont. I find for instance young specimens in a 

 shale collected by T. N. Dale on Hamilton hill near Fair Haven in southern 

 Vermont. 



The wide distribution of this important index fossil of the closing 

 period of the Cambric in Canada and Europe has been discussed in detail 

 by the present writer [1903]. In Canada it has been reported by Dawson 



Fig.26 Dictyonema 

 flabelliforme Eich- 

 waia (sp.) Fragment of 

 branch showing lateral 

 view of thecae and aper- 

 tures of flanking tubes 

 ("gonangia"). Schaghti- 

 coke. xS 



^Mr van Ingen informs me that he collected, in the St John basin, specimens 

 having a lengtii of 10 to 12 inches. 



