640 NEW YORK STATE :SIUSEUM 



ing branclies is about 140° with variations, partly perhaps by somewhat 

 oblique compression, to 100° on the one and to 170° on the other hand. The 

 branches are in many specimens nearly straight in the initial part, in the 

 majority, however, they have a slight concave curvature. The formation of 

 the secondary branches [fig.7] is accomplished like that of the primary ones, 

 by rapidly repeated gemmation [fig. 11]. The secondary branches are dis- 

 posed unsymmetrically, as the figures well illustrate, the bifurcation in the 

 rhabdosome often taking place in one branch a short distance from the 

 sicula, in the other very distally or not at all. In no case, hov^ever, has 

 the bifurcation been observed so close to the sicula as in B . k j e r u 1 f i , 

 callavei oi- i- a m o s u s , The branches are very slender, theii- maximum 

 width being only about . 5 mm. 



The thecae are long, narrow tubes of nearly uniform width, or very 

 slightly "svidening to^vard the aperture. They number quite constantly 10 

 in 10 mm, which number in a few cases sinks to 9, 8 or even 7 ; they are 

 overlapping one third to one half of their length, are about five times as 

 long as wide and diverge 15° to 20" from the axis of the branches. 

 Their outer walls are straight or very slightly concave. The apertural margins 

 are straight and form an oblique angle with the branch. 



Position and locality. B . 1 a p w o r t h i is common in graptolite bed 

 1 and very common in graptolite bed 2 of the Deep kill section, 



Semarhs. This form is closely related to the specimen from the 

 Lower Skiddaw slates at Barf, doubtfully referred by Marr [1894, p. 130] 

 and Elles [1898, p,470] to B. callavei Lap worth, and lately described by 

 Elles and Wood as B , d i v e r g e n s , It, however, happens so that one 

 difference between the specimen mentioned and the species described by 

 Lapworth is here still more emphasized, i. e. the branches possess a still 

 wider divergence. Moreover, the bifurcation of the branches in none of 

 the specimens takes place so near to the sicula as in the specimen from 

 Barf or in the types of B. callavei, though in this regard a great 

 diversity prevails among the specimens, as is evinced by the figures 

 [pl.5, fig.9, 10]. Our form differs from B. divergens, besides, in the 



