64 TEENTON PERIOD. 



sliai-ply rounded or angular at the bottom: inner and outer sides botli ris- 

 ing at acute angles witli the axis of the stipe, those of adjacent cells join- 

 ing together to form moderately long, slender, mucronate points, Avhich are 

 directed sti'ongly iipward between the cells. At the basal end of the stipe 

 small, downward-diverging points are sometimes seen, such as those pos- 

 sessed by G. Whitfieldi Hall, and other allied species; like those species 

 also, oiu's has a slender, tln-ead-like axis, passing longitudinally through the 

 center of the stipe and extending beyond the distal cells; sen-atures, or cells, 

 about twelve in the length of a centimeter, but they have the aspect of 

 being somewhat more numerous, because of the naiTowness of the cells 

 occasioned by the acuteness of the angle which the cell-axes form with the 

 axis of the stipe. Exterior width of the stipe between the mucronate points 

 of each side often less than two millimeters, and seldom more. Length of 

 stipe, from one to three centimeters. 



Upon the pieces of graptohtic shale in the collections are numerous 

 stipes doubtless belonging to this species, but most of them have their 

 details of structure so far obscured that it is difficult to distinguish them; 

 the mucronate points between the cells, being delicate, are often removed, 

 in which case the sen-atures have a blmited appearance. The more perfect 

 stipes have somewhat the aspect of portions of those of Hypmim, or other 

 related mosses, which circumstance has suggested the specific name. 



This species is related to G. Wliitfieldi Hall from the graptolitic shales 

 at Noiman's Kill near Albany, NewTork; but the prolongations of the cell- 

 walls are mucronate, pointing upward, in ours, and not setseform, pointing- 

 outward, as in that species. Ours is also a smaller and more slender species, 

 and has proportionally narrower cells. 



Position and locality. — Shales, probably of the age of those at Noi-man's 

 Kill, near Albany, New York; five miles north of Belmont, Nevada, where 

 it is associated with the last described, and also with the two following 

 species. 



