1915] PALAEOZOIC FOSSILS FROM HupsoN Bay. 55 
Devonian, and as all the characters are not presented by any one shell, 
I have made the reference to this genus provisional only. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 419 S. Royal Ontario Museum of Palaeontology. 
SILURINA (?), sp. indet. 
Plate V, figure 9. 
The collection contains one extremely poor cast of the left valve 
of an ovate Pelecypod measuring 65 mm. by about 50 mm. The valves 
are rather flat, with the greatest thickness above and in front of the 
mid-point. The total thickness of a cast would not exceed 24 mm. 
There is no evidence of the beak or of the hinge line. The antero- 
ventral margin is distinctly crenulated as if the shell gaped a little at 
that point. 
I have been unable to find any American Silurian shell with which 
this specimen is comparable except possibly Ilionia (Prelucina). 
Barrande figures a number of shells, mostly from his Etage e2, under 
the generic name Silurina. Some examples of Silurina distorta, par- 
ticularly that figured as No. 23, Plate 42, Vol. VI, Systéme Silurien de 
la Bohéme, approaches closer to our specimen than any other species I 
have been able to find. It is unfortunate that the specimen is so imper- 
fect as to render its identification uncertain, but I cannot do better than 
to refer it provisionally to Silurina. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 429 S. Royal Ontario Museum of Palaeontology. 
GASTROPODA 
BELLEROPHON, sp. indet. 
Plate IV, Figure 5. 
A single imperfect cast of the interior. The general form of the 
shell is globular, but it is somewhat extended towards the aperture, 
which appears to be but little expanded. No evidence is presented of 
the existence of a slit band or transverse markings, but towards the 
aperture the dorsum becomes much more acuminate than in the major 
portion of the shell. The whorls are closely wound and overlapping, 
leaving a small umbilicus. The inner lip was strengthened by a strong 
callosity which appears in the cast as a deep circular pit surrounding 
the stony matter filling the umbilicus. The outer side of this cavity 
