127 
—_—. 
SS) 
the ventral valve has a superficial resemblance. The ventral valve of 4. wmbonata is readily 
recognized by its very gibbous form, its extremely elevated and incurved beak, its possession 
of a distinct mesial sinus extending from the beak to the front margin, and the existence of a 
high and conspicuous area with a well marked fissure. 
Locality and Formation.—Corniferous Limestone, Port Colborne. 
160. CRANIA ORENISTRIATA (Hall). 
Crania crenistriata (Hall), Thirteenth Report on the State Cabinet, p. 78. 
Crania crenistriata (Hall), Pal. N. Y., Vol. IV, p. 28, Pl. III, fics, 13—16. 
On examining the surface of some of the Heliophylla of the Hamilton group, to which 
80 many small organisms are attached, I find several specimens of Crania crenistriata (Hall). 
The dorsal valve of this species is all with which I am acquainted, and it is depressed-conical, 
nearly circular, with a central or sub-central apex. The apex is smooth, and the remainder 
of the shell is covered by sharp elevated crenulate radiating striz, which increase interstitially, 
and of which there are about ten in the space of one line at. the margin. The diameter of 
an individual of medium size is two lines and a half the height of the valve being little over 
half a line. 
The ventral valve has never been detected, and Hall has only seen four specimens of the 
dorsal valve ; but the species does not appear to be very rare in the Hamilton shales at Arkona. 
Locakity and Formation.—Hamilton Formation, Bartletts’ Mills, near Arkona, Town- 
ship of Bosanquet. 
LIST OF FOSSILS FROM THE CORNIFEROUS AND HA- 
MILTON FORMATIONS OF WESTERN ONTARIO. 
(The letters C. and H. indicate the occurrence of the fossil in the Corniferous Limestone 
or Hamilton Formation.) 
I. Protozoa. 
1. Astreeospongia Hamiltonensis, Meek and Worthen ? (C). 
2. Stromatopora tuberculata, Wicholson (C). 
3. perforata, Nicholson (C). 
4. ce granulata, Nicholson (C and H). 
5. “ mammillata, Nicholson (C). 
6. es concentrica, Goldfuss ? (C). 
II. Ca@LENTERATA. 
. Blothrophyllum decorticatum, Billings, (C). 
8. approximatum, Nicholson (C). 
9. Clisiophylinm Oneidaense, Billings (C). 
10. pluriradiale, Nicholson (C). 
11. Zaphrentis gigantea, Le Sueur (C). 
12. se fenestrata, Nicholson (C). 
13. ag prolifica, Billings (C). 
14, 5 spatiosa, Billings (C). 
