GRAPTOLITES. 125 
PHYLLOGRAPTUS ANGUSTIFOLIUS, Hall. 
Plate XVI, figures 17-21. 
(Pu. anaustirorivs, Hall: Geological Survey of Canada, Report for 1857, page 139.) 
Description.—The stipes, as seen on the slaty lamine, are elongato-ellip- 
tical or elongato-lanceolate, being usually a little broader near the base. 
Radicle scarcely visible: margins celluliferous ; cellules about twenty-four 
in the space of an inch (rarely twenty-six, while one short broad form 
shows twenty-eight) ; cell-apertures with an elongate triangular denticle, 
which is mucronate at the extremity: the denticle is once and a half as 
long as the width of the cell. Central axis from three to four hundredths 
‘of an inch in width, obscurely indented by the cellules of the other divisions 
of the frond. 
This species differs from either of the preceding in its narrow and elon- 
gate form. The specimens are numerous, but being for the most part on 
slaty laminze which are extremely compressed, they preserve scarcely any 
substance ; a mere outline, with a more brilliant surface than the rest of 
the rock, being almost the only remaining characterby which they are 
recognized. In a few individuals the test is better preserved, showing a 
moderate thickness. The cell-margins on the upper side are less extended 
on the cell-partitions than in the preceding species ; while on the lower side 
they are equally or more extended, giving a form of aperture different 
from that of the other species, and a different denticle. 
EXPLANATIONS OF Figures oF PHYLLOGRAPTUS AUGUSTIFOLIUS, Hall. 
PiatTe XVI. 
17.. A small and comparatively wide specimen, with a distinct linear axis, but 
without evidence of cellules. 
18. A more elongate specimen, with distinct axis, with a darker line in the centre. 
19, 20, 21. Varieties of form and proportion. The specimen fig. 21 is the largest 
observed. . 
This species is placed under Phyllograptus from its similarity in form to 
others of the genus, although evidenee of the quadruple division has not 
been established. The want of parallelism of the margins, and the sub- 
elliptical form would, I conceive, be sufficient to remove it from the genus 
Diplograptus. 
Formation and Locality— Quebec group; Point Lévis. 
