GRAPTOLITES. . 93 
The specimen lies with the celluliferous face downwards, and the stipes 
near their origin present only the back, which shows them to be strong, 
and of considerable substance, and measuring at that point five hundredths 
of an inch in width. Extending from the disc, the stipes are gradually 
turned on one side, and in their greatest width measure seventeen hun- 
dredths of an inch in diameter, including the denticles. Cell-denticles 
sub-mucronate, rising above the margin almost vertically; about twenty- 
two in the space of an inch. 
This species preserves the general form of G. quadribrachiatus; but 
is more robust, and the stipes are united in a central disc. The specimen 
is upon a weathered surface, and very obscure; the characters being 
drawn from the general form and proportions. The cell-denticles are 
visible on a part of three of the stipes, but we are unable to trace the 
direction or existence of any cell-partitions. The denticles in their 
prominence resemble those of G. denticulatus ; and broad stipes of G. 
bifidus have likewise some analogy with this species; but as our only 
specimen is imperfect, no minute comparisons can be made. It is a 
smaller species than G. Headi, but with a comparatively broader stipe, 
and more erect cell-denticles. In G. crucifer the disc is quadrilateral, 
with concave sides, and is somewhat oblong; while in G. Headi the disc 
is larger and essentially square, the margins being very nearly straight. 
In the specimen described, the disc is without markings, as are also some 
other discs which may belong to this species; while a single specimen 
shows concentric strize parallel to the margins. 
EXPLANATIONS OF Figures OF GRAPTOLITHUS CRUCIFER, Hall. 
PuatTE VY. 
10. View of the specimen from which the description is drawn. 
13. The dise of a young individual probably of this species. 
Formation and Locality—Shales of the Quebec group; Point Lévis. 
17. GRAPTOLITHUS ALATUS, Hall. 
Plate VI, figure 9. 
(G. auaTus: Geological Survey of Canada, Report for 1857, page 127.) 
Description.—Frond consisting of four stipes (probably simple) ; their 
bases united in a thickened disc, the central portion of which is about seven 
tenths of an inch in extent, and uniting to the stipes continues along their 
