S09 



PALEONTOLOGY OF NEW YORK. 



GraptolithiiH logani. 



P^^ 



Graptolitlius Iog:aiii. 



Frond composed of numerous branches nearly equally disposed on two 

 sides of a central connecting stipe, and each again subdividing nearly 

 equally ; after which they bifurcate, always near the base, with greater 

 or less regularity : connecting membrane thin, composed of the same 

 substance and continuous with the branches, extending from the centre 

 to some distance beyond the bifurcations. The branches, after the third 

 bifurcation, become marked on the inner side by a row of cellules, and 

 along the centre by an abruptly impressed line which follows the di- 

 varication of the branches : cellules minute, not prominent towards the 

 base of the branches, being compressed vertically, and appearing like a 

 double series with a central depressed line, becoming developed as they 

 recede from the base. The branches beyond the disc are turned on one 



