LOWER CRETACEOUS ROCKS OF BRITISH COLUMBIA. 83 
a little further to the north. Another example was collected by Dr. G. M. Dawson on 
the north slope of Jackass Mountain. 
PHOLADOMYA VANCOUVERENSIS, Sp. Nov. 

Fic. 2. PHoLADOMYA VANCOUVERENSIS. 
Shell swollen and convex in front of the middle, obliquely compressed behind. 
Valves very inequilateral, transversely subovate, gaping a little behind and nearly closed 
in front. Anterior end very short, contracted both above and below, and subtruncated at 
the extremity ; posterior end elongated, rounding gradually into the basal margin below 
and more abruptly above into the superior border. Cardinal margin nearly straight for 
some distance behind the beaks and sloping downwards very abruptly in front of them. 
Basal margin produced and gibbous in the centre. Umbones depressed, rather wide but 
narrowing rapidly into the abruptly attenuated, slender and acute beaks, which curve 
distinctly inwards, downwards, and a little forwards. The position of the beaks is ante- 
rior, and they are very nearly but not quite terminal. From the anterior side of the beak, 
ineach valve, a faint ridge descends in a nearly vertical line to the junction of the ventral 
with the anterior border, and immediately behind this ridge there is a slight inflection of 
the test below. 
Surface marked by coarse concentric sulcations, and by a few faint, centrally disposed 
radiating striæ. 
Length, twenty lines; height, behind the beaks, thirteen lines and a half ; maximum 
convexity, twelve lines. 
North-east slope of Jackass Mountain, in the valley of the Lower Fraser. Two speci- 
mens. : 
This Pholadomya appears to be somewhat closely allied to the P. Uralensis of D’Orbigny, 
but it is a smaller shell, with much more depressed beaks, and a very different style of 
surface ornamentation. 
GONIOMYA. 
A small fragment of a species of Goniomya was collected by Dr. Dawson at the same 
locality as the fossil last described, but it is impossible to identify such an imperfect spe- 
cimen. 
