121 
Inoceramus pontoni n. sp. 
Plate XX, figures 1, 2 
Holotype longer than high, not oblique, very convex. Beaks anterior, 
incurved and curved slightly forward; postumbonal slope prominent, 
rounded, a very slight sulcus behind it; anterior part of shell inflected and 
has pronounced, curved sulcus. Equi valve. Hinge-line long; anterior 
margin rounded; basal margin very gently rounded; posterior margin 
rounded. Fairly strong concentric corrugations. Length 47 mm., height 
36 mm., thickness right valve 18 mm. 
A very variable species. In some specimens the anterior inflected 
area is almost flat. Other specimens are much less convex, others more 
convex than the holotype. The narrow sulcus posterior to the postum- 
bonal slope is very well marked in some specimens, whereas in others it is 
very faint. In some specimens there is a differentiation of the concentric 
corrugations into two sizes, the stronger separated by a number of smaller 
concentric corrugations. There is also much variation in size. 
Inoceramus cordiformis Sowerby 1 is a proportionately higher shell, 
the sulcus on the postumbonal slope separates two rounded ridges and the 
anterior area is bounded in some specimens by a rounded ridge. This 
British species also is more compressed and wing-like in the postero-dorsal 
angle. 
The name is given for G. M. Ponton, mining engineer. 
Horizon and Locality . In Bad Heart sandstone, east bank Smoky 
river, below mouth of Puskwaskau river; fresh talus from same. In fresh 
talus of Bad Heart sandstone from east bank of Smoky river, about 1| 
miles below Puskwaskau river. In talus south bank Smoky river about 
2 miles below mouth of Bad Heart river, probably from Bad Heart sand- 
stone. In a lot labelled “talus from Bad Heart sandstone and concretions 
in shale below,” east bank Smoky river about 3 miles below Puskwaskau 
river; probably from the Bad Heart. Thirty-five miles above mouth of 
Little Smoky on Smoky river, collected by Coulthard and Ponton. 
Type. Victoria Memorial Museum; holotype, Cat. No. 6103. 
Inoceramus coulthardi n. sp. 
Plate XXI, figures 1-4 
About equivalve, higher than long, much swollen. Prominent, 
rounded, postumbonal slope; beaks anterior, produced, incurved and a 
little curved forward. Anterior part of shell strongly inflected, concave 
and demarcated from remainder of valve by angular ridge; in some speci- 
mens flattened in postero-dorsal angle. Strong concentric corrugations, 
the interspaces covered with finer concentric corrugations. 
Length 22 mm., height 30 mm., thickness of a single valve 16| mm. 
Differs from Inoceramus pontoni n. sp. in smaller size, greater pro- 
portionate height, more produced beaks, more inflected, more sharply 
demarcated, and more concave anterior area, and the lack of a sulcus on 
the postumbonal slope. 
1 See Woods, Henry, “Cretaceous Lamellibranchia,” Pal. Soc., 1912, p. 334, PI. 53, fig. 8, PL 54, figs. 2-4. 
