82 CANADIAN FOSSILS. 
EXPLANATIONS OF Figures or GRAPTOLITHUS EXTENSUS, Hall. 
Puate II. 
11. A single stipe more than four inches long, with the radicle and part of the 
opposite stipe. 
12. A fragment showing a part of the stipe on each side of the radicle, natural size. 
13. The radicle and adjacent cellules, enlarged from fig. 12. 
14. An enlargement of fig. 12 at a point about two inches from the radicle. 
15. A fragment of a stipe where the cellules are distended by iron pyTiies: This 
fragment may belong to a different species. 
16. An enlargement from fig. 15. 
Formation and Locality.—Shales of the Quebec group ; Point Lévis. 
10. GRAPTOLITHUS PENNATULUS, Hall. (a. s.) 
Plate III, figures 1-8 ; and Plate V, figure 9. 
Description—Frond consisting of two stipes, which diverge rectangu- 
larly, or are more or less ascending from a small radicle. Stipes narrow 
at the base, gradually or rapidly increasing in width for about two thirds of 
their length. At the base they measure not more than three or four hun- 
dredths of an inch, and increase to one tenth of an inch in the narrower indi- 
viduals ; while the widest observed is three tenths of an inch at one third of 
the length from the base, beyond which point it is somewhat narrower. They 
are all more or less contracted towards the distal extremity, curved on the 
celluliferous side, and nearly straight on the back: the terminal cellules are 
developed in a line nearly parallel with the axis. The proportion of the 
stipe occupied by the common body is from one seventh to one fourth of 
the entire width. The test is apparently smooth ; that of the back of the 
stipe and partitions of the cells seems to be considerably thicker than the 
outer walls of the cellules. 
The cellules, when fully developed, are long, narrow, and curved up- 
wards, making an angle with the axis of from 30° to 45° im different indi- 
viduals at the base of the cellules, and as high as 70° on the outer part of 
some of them; while the average angle, taking a line from the base to the point 
of the cellule, is from 50° to 57°. The line of the aperture is curved : the 
pellicle forming the cell-walls extends along the posterior side of the cell- 
partition next in advance, the line of aperture making an angle with the 
axis of from 110° to 120°; while the extremity of the denticle is 
mucronate. ‘The fully-developed cellules have a length of eight times 
