1915] PALAEOZOIC FossILs FROM Hupson Bay. 51 
PENTAMERUS OBLONGUS, Sowerby. 
PENTAMERUS LAEVIS, James Sowerby. Min. Con., Vol. I, p. 76, pl. 28, 1813. 
PENTAMERUS OBLONGUS, J. de C. Sowerby. Silur. Syst., pl. 19, fig. 10, 1839. 
PENTAMERUS OBLONGUS, Hall. Geol. Rep. 4th Dist., N. York, p. 7, figs. 1-5, 1843. 
PENTAMERUS OBLONGUS, Whiteaves. Geol. Sur. Can., Palaeoz. Foss., Vol. III, pt. II, 
p. 63, 1895. (See this article for extended synonomy.) 
This well known species is represented by a single example which 
I am unable to differentiate from Sowerby’s species. The form re- 
sembles almost exactly the example figured by Whitfield in Figure 4, 
Plate 17, Wisconsin Geological Survey, Volume IV. 
Locality—Above Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 390 S. Royal Ontario Museum of Palaeontology. 
CONCHIDIUM cf. DECUSSATUM, Whiteaves sp. 
PENTAMERUS DECUSSATUS, Whiteaves. Can. Rec. of Sci., Vol. IV, 295, pl. 3, figs. 3 and 4, 
1891. 
CONCHIDIUM DECUSSATUM, Hall and. Clarke. fal, (IN. York, Vol; VEL) pt. 2; px 235; 
pl. 65, figs. I and 2; pl. 66, fig. 15, 1894. 
CONCHIDIUM DECUSSATUM, Whiteaves. Geol. Sur. Can., Palaeoz. Foss., Vol. III, pt. IV, 
p. 293, pl. 26, figs. 1 and 2, 1906. 
The collection contains three fragments which are provisionally 
referred to this species. One fragment from the drift at the mouth of 
the Nelson river (No. 391 S) shows part of a brachial valve very closely 
resembling Whiteaves’ figures. A second specimen from the same 
locality (No. 392 S) is an internal cast of a pedicle valve which resembles 
the type figures in a less satisfactory manner, as the strongly arched 
outline of the shell is not apparent in our specimen. A third specimen 
(No. 393 S), also from the Nelson river, is so deformed by pressure that 
its identity with the others is conjectural only. The fourth specimen 
(No. 394 S) is a cast of a brachial valve indicating a shell flatter than 
No. 391 S and apparently more finely striate. I very much doubt the 
identity of this fragment with the others. 
Conchidium decussatum was described by Whiteaves from material 
obtained at the Grand Rapids of the Saskatchewan river, and it is not 
recorded by him in the lists of specimens from the Ekwan and Atta- 
wapiskat rivers. 
In referring all the present examples to this species, I am exceeding 
their proved identity, but the material is much too imperfect to warrant 
description, and it seems better, provisionally, to place them all under 
this species. 
Locality—Drift, mouth of Nelson river, District of Patricia. 
Horizon—Probably Silurian. 
Nos. 391 to 394 S. Royal Ontario Museum of Palaeontology. 
