1915] PALAEOZOIC FOSSILS FROM HUDSON Bay. 47 
STROMATOPOROIDEA 
STROMATOPORA CONSTELLATA, Hall. 
STROMATOPORA CONSTELLATA, Hall. Pal. N. York, Vol. II, p. 324, pl. LX XII, figs. 2a 
and b, 1851. 
STROMATOPORA CONCENTRICA, Hail. Pal., N. York, Vol. II, pl. LX XIII, figs. 2, 2a and 
2b, 1851. 
COENOSTOMA CONSTELLATUM, Spencer. Bull: Univ. State of Miss., Vol. I, no. I, p. 48, 
pl. VI, fig. 11, 1882. 
STROMATOPORA CONSTELLATA, Whiteaves. Can. Rec. Sci., Vol. VII, p. 137, 1896. 
STROMATOPORA HUDSONICA, Dawson. Quart. Jour. Geol. Soc., Vol. XXXV, p. 52, pl. IV, 
figs. 9a and gb; pl. V, fig. 10, 1879. 
STROMATOPORA HUDSONICA, Nicholson. Mon. Brit. Strom., Pal. Soc., p. 172, 1891. 
STROMATOPORA HUDSONICA, Nicholson. Ann. and Mag. Nat. Hist., p. 312, pl. VIII, 
figs. I-3, 1891. 
STROMATOPORA CONSTELLATA, Parks. Ottawa Nat., Vol. XXII, p. 28, 1908. 
STROMATOPORA CONSTELLATA, Parks. Univ. of Toronto Studies, Geol. Ser., No. 5, p. 44, 
pl. XIII, figs. 7, 8 and 9, 1908. 
Several specimens indifferently preserved, but one of which shows 
the astrorhize in an excellent manner.’ Some of these examples were 
erroneously referred to Actinostroma tenuifilatum in the preliminary 
report. 
Locality—Limestone rapids, Severn river, District of Patricia, Ontario. 
Horizon—Silurian. 
No. 410 S. Royal Ontario Museum of Palaeontology. 
CLATHRODICTYON CYSTOSUM, Rominger sp. 
STROMATOPORA VESICULOSA, Rominger. Proc. Acad. Nat. Sci. Phil., p. 50, 1886. 
STROMATOPORA CysTosA, Rominger. MSS. United States National Museum labels. 
CLATHRODICTYON CysTosuM, Parks. Univ. of Toronto Studies, Geol. Series, No. 5, p.21, 
5; pl. VII, figs. 2, 3 and 4; pl. VIII, figs. 6 and 8, 1908. 
CLATHRODICTYON CysTosuM, Parks. Univ. of Toronto Studies, Geol. Series, No. 6, 
p. 29, 1909. 
This species is represented by a fragment from a large coenosteum 
in which the structure is very well preserved. Sections indicate a close 
resemblance to the type of C.cystosum, but they also show some points 
of difference. The chief variation is seen in the vertical arrangement 
of the cysts in some parts of the ccoenosteum whereby the vertical 
elements appear more pronounced than the horizontal; this effect is 
1Jn the works above mentioned I have recorded the occurrence of the following 
species of Stromatoporoids in the Silurian of the Hudson Bay region: Clathrodictyon 
vesiculosum, C. drummondense, C. fastigiatum, C. cystosum, C. cystosum lineatum, C. 
cystosum cylindricum, C. striatellum, C. vesiculosum minutum, Actinostroma tenutfilatum, 
A. tenuifilatum inflectum, A. franklinense, A. tenuifilatum cylindricum, Stromatopora 
constellata, S. wilsont, S. carteri, S. amit, S. ndianensis, Actinodictyon neptunt, A. keelet, 
and A. low. 
