78 CANADIAN FOSSILS. 
7. GRAPTOLITHUS SIMILIS, Hall. (n. s.) 
Plate II, figures 1-5. 
Description.—Frond consisting of two narrow sublinear elongate stipes, 
proceeding from a small pointed radicle, from which they diverge almost 
rectangularly : stipe acquiring its full width near the radicle, having a 
short space near the base without cellules ; extremities somewhat rounded, 
from the partial development of the cellules. The stipe varies from five 
to ten hundredths of an inch in width: the cell-partitions, when visible, 
extend nearly to the back of the stipe, leaving a narrow space occupied by 
the common body. Surface nearly smooth : cell-partitions seldom seen, and 
not distinetly visible ; the specimens extremely compressed. 
Cellules somewhat short and broad, little curved, about twenty-one 
in the space of an inch, inclined at an angle of 23° to the axis. The 
cellules are from two to three times longer than wide, this depending 
on the width of stipe: margin of aperture truncate, making an angle 
with the axis of from 118° to 180°; the cell-walls show obscure striae 
parallel to the aperture. The apex of the denticle is vertically above the 
posterior basal edge of the second cellule in advance. 
The nearest affinities of this with any American species are with those 
designated by me as G. sagittarius and G'. serratulus from the shales 
at Norman’s Kill, near Albany ; but the cellules make a much less 
angle with the axis of the stipe, and the whole body is less robust than 
the larger specimens of Gt. sagittarius. It bears a remote resemblance 
to the figures of G. nuntius of Barrande, as given both by Barrande 
and Geimitz; approaching more nearly to the figures of G. sagittarius 
of Hisinger, as given by Geinitz, than to any of the others; though these 
figures give a higher angle between the axis and the direction of the 
cellules. The angle made by the cellules of: G. nuntius with the axis, 
as given by Barrande, is 45°, which corresponds with our Norman’s 
Kill specimens ; but they differ in other respects. The present species 
differs from most of the other Canadian species in the straightness of its 
stipe ; and in the low angle made by the cellules, from all others, except 
G. indentus. 
The specimens are replaced by pyrites in a dark or nearly black slate, 
and associated with other forms too imperfect to be identified ; one of them 
resembling G. guadribrachiatus, and another G. bryonoides. 
