1915] PALAEOZOIC FOSSILS FROM HUDSON Bay. 53 
This common species occurs in the Niagara of America as well as 
in corresponding Silurian strata of Europe. It is also recorded in the 
Guelph and is referred to by many authors. The occurrence in the 
present association is rather to be expected, but we have only one 
specimen partly buried in matrix. Whiteaves (op. cit.) describes and 
figures a small form from the Ekwan river in which the ribs are narrow 
and angular instead of broad and rounded; our specimen is nearer the 
type than the variety figured by Whiteaves. 
Locality—Above Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 395 S. Royal Ontario Museum of Palaeontology. 
DELTHYRIS; sp. indet. 
Plate III, Figure 13. 
DELTHYRIS cf. SULCATUS, Parks. Bur. Mines of Ont., 22nd Rep., pt. I, p. 195, 1913. 
A single cast of one valve partially imbedded in matrix. The general 
appearance suggests Delihyris sulcatus, Hisinger sp., but the mesial fold 
is not developed. The shell is about 15 mm. wide and seven or possibly 
eight mm. in height; it is marked by three prominent rounded ribs in 
the median region and by three similar but smaller ribs towards the 
angles. The specimen is much too imperfect to warrant a specific 
name; provisionally it may be regarded as related to Delthyris sulcatus. 
It is on the basis of this resemblance only that the species is referred to 
Delthyris. 
Locality—Above Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 397 S. Royal Ontario Museum of Palaeontology. 
MERISTINA (?) EXPANSA, Whiteaves. 
MERISTINA (?) EXPANSA, Whiteaves. Geol. Sur. Can., Ann. Rep., Vol. XIV, pt. F., p. 45, 
1904. 
MERISTINA (?) EXPANSA, Whateaves. Geol. Sur. Can., Palaeoz. Foss., Vol. III, pt. IV, 
p. 245, pl. 27, figs. 6, 6a and 7, 1906. 
The collection contains three specimens of small size (about 20 mm. 
in diameter) which conform closely with Whiteaves’ description. The 
shell is preserved, but the outer layer has exfoliated partially, but not 
enough to expose the concentric ornamentation figured by Whiteaves. 
The most perfect shell has a practically smooth exterior, and seems to 
indicate a perforation in the beak of the pedicle valve. 
Locality—Above Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 398 S. Royal Ontario Museum of Palaeontology. 
