8 TRANSACTIONS OF THE ROYAL CANADIAN INSTITUTE. [VOL. x1 
WHITEAVES, J. F.—The Fossils of the Silurian Rocks of Keewatin, 
Manitoba, the Northeastern Shore of Lake Winnipegosis, and 
the lower Saskatchewan River. Geol. Sur. Can., Pal. Fossils, 
Vol. III, Pt. 4, pp. 243-296, 1906. 
WHITEAVES, J. F.—Notes on Cyrtoceras cuneatum. Ottawa Nat., Vol. 
XX, pp. 133-134, 1906. 
WHITFIELD, R. P.—Observations on and Descriptions of Arctic Fossils. 
Am. Museum of Nat. Hist., Bull. 13, pp. 19-22, 1900. 
The descriptions herein contained are compiled as follows: 
I. Ordovician species. 
II. Species from Ordovician drift. 
III. Silurian species. 
IV. Species from Silurian drift. 
V. Species from the drift of doubtful age. 
Pr 
ORDOVICIAN SPECIES 
The following species were obtained chiefly from the lower rapids 
of the Shamattawa river, which enters Hudson Bay near Port Nelson. 
The horizon is Trenton, but the assemblage of fossils indicates a slightly 
different position from the Trenton of Baffin Land. 
PORIFERA 
AULOCOPIUM (AULOCOPELLA?) GIGANTEA, sp. nov. 
Plate V, Figure 7. 
This species is represented by a single fragment, 110 mm. long, 
70 mm. wide and about 15 mm. thick. The curvature of the canals and 
the divergence of the skeletal elements indicate that the diameter could 
not have been less than 300 mm. 
The polished vertical section of the specimen shows large concentric 
canals of about 3 mm.in width. The canals are not round, but elliptical, 
with the greater diameter in the plane of section: they are 2 to 3 mm. 
apart in the plane of section and rather less in the opposite direction. 
Smaller radial pores traverse the tissue at right angles to the larger 
concentric pores. The radiating skeletal elements appear to the 
number of 5 or 6 in the space of one mm. 
There can be little doubt that this specimen represents a species of 
the genus Aulocopium, but its reference to the sub-genus Aulocopella 
is less certain. Regarding this sub-genus Rauff says: ‘“‘ Untergattung 
