12 
A compressed sphaerocone of Macrocephalitoid aspect, with almost 
complete body-chamber not quite a whorl in length. Signs of gerontic 
inflation towards end of body-chamber, with versiradii passing straight 
over venter, having lost the ventral curvature of the early part of whorl. 
The subangustumbilicus is gradate, with walls falling about at right 
angles to the median line of the conch. Primary ribs about 26, short, 
slightly curved until near end of body-chamber, furcating about on L2. 
For some remarks on the significance of curved ventral ribs See later 
under Miccocephalites , page 14. 
To Macrocephalites aff. lamellosus Burckhardt (1, p, 31, PL III, figs. 
7, 8), from Lowest Callovian, Comisaria Lonquimay, Argentina, the 
Canadian species shows great resemblance. There is, however, a slight 
difference in the ribbing, principally that in the Canadian shell the ribs 
are shorter, stronger, and rather more curved. The proportions of Burck- 
hardt’s shell are given by him (p. 32) as T.41, 51, 56, 19, Ammonites 
lamellosus J. de C. Sowerby (Pl. XXIII, f. 8) is quite a different form, with 
which the Canadian shell could not be compared; but the likeness of the 
Canadian and Argentine shells is near enough to suggest synchronism of 
deposits. 
To Macrocephalites kitchini Uhlig (p. 271, PL LXXVII, 6), this species 
bears very considerable resemblance. The proportions of Uhlig’ s form 
are nearly the same, T.37-5, T.49 (F. 50), T.19, but there is much differ- 
ence in ribbing — particularly, in the Canadian shell, the primary ribs are 
stronger, shorter, and more curved. The secondaries also are stronger. 
An intricate suture-line is depicted by Uhlig: nothing so elaborate is to 
be found in the Canadian shell, even allowing for its indistinctness. Uhlig’s 
shell is from the Spiti Shales, Himalaya, and its horizon is given as “Oxford- 
ian?” 
Macrocephalites pila Bukowski (Pl. XXVI, fig. 17) is another form 
with which M. metastatus may be compared. The ribbing having in lateral 
and ventral flexure much likeness to that of the Canadian shell shows that 
it is not the Russian species of Nikitin and in proportions given by Bukow- 
ski F. 32, 40, 78, 18 (p. 127) 1 it differs altogether from the Canadian species. 
Bukowski’s form is from Poland, from “obere Abtheilung des Callovien.” 
According to the other species figured by him with this statement this 
covers many horizons, mainly about the date of English Oxford Clay. 
There is no fauna of the Kellaways Rock of southwest England figured by 
him, though constituents of such fauna occur elsewhere in eastern Europe: 
hence it is to be concluded that his Macrocephalite is not of that date. 
If contemporaneity with Kellaways Rock were claimed the local absence 
of the essential fauna would require much explanation. An earlier or 
later date for the Macrocephalite would not require this. Bukowski 
seems to suggest that it is later, but in Europe the bulk of Macrocepha- 
litidae are of much earlier date than Kellaways Rock, though there are 
traces of them in the rock (See later, page 17). Farther afield Macro- 
eephalitoidae occur later than the Kellaways Rock, but it has yet to be 
proved that they are Macrocephalitidae. Bukowski ’s Macrocephalite 
may be a fortuitous relic of a pre-Kellaways deposit: its association with 
1 The figure gives F. 32, 47 , 80, 16. 
