110 CANADIAN FOSSILS. 
DIPLOGRAPTUS PRISTINIFORMIS,* Hall. 
Plate XIII, figures 15-17. 
(GRAPTOLITHUS PRISTINIFoRMIS, Hall: Geological Survey of Canada, Report for 1857, 
page 133; Geology of Canada, 1863, page 955. FucompEs DENTATUS: Brongniart, 
Histoire des Végétaux Fossiles, vol. 1, p. 70, 1828. 
Description.—Stipe flattened simple sub-linear, celluliferous on the two 
sides, narrower at the base, obtuse, showing an extended slender radicle, 
gradually expanding above and obtaining its full width (about eight 
hundredths of an inch) within half an inch from the base. Cellules 
narrow, Closely arranged; the free extremity sometimes acute, some- 
times obtusely rounded ; inclined to the axis at an angle of less than 
20° ; from six to eight times as long as wide, a little more than one third of 
their length free: angle of the aperture with the axis very variable, de- 
pending on the direction of the compression. About twenty-eight cellules 
in the space of an inch. Axis strong, often extending considerably beyond 
the celluliferous portion of the stipe, and sometimes marked by a groove 
indicating a line of separation. 
This species bears some general resemblance to G. pristis (Pal. N. Y., 
vol. i, p. 265, pl. 72, fig. 1); but the stipe is narrower, and the cellules 
narrower and more closely arranged. In general form it resembles G. 
“angustifolius ; but in that species the margin is more deeply indented, the 
cell-denticles are always rounded, and the cellules inclined at a higher 
angle to the axis. 
EXPLANATIONS OF Figures oF DiPLOGRAPTUS PRISTINIFORMIS, Hall. 
Puate XIII. 
15. A fragment of a stipe, showing the usual form and proportions of the best- 
preserved specimens. 
16. A smaller individual, with the mid-rib or axis extending beyond the body of 
the stipe. 
17, An enlargement from fig. 16, showing more distinctly the form of the cellules. 
Formation and Locality.—Quebec group ; Point Lévis. 
* This species is probably identical with Fucoides dentatus, Brongniart, ut cit. See 
note under G, bryonoides, page 84, 
