22 
CHRONOLOGY 
The English Macrocephalitid forms which have the most resemblance 
to those from the Feraie formation of Alberta are Catacepkalites from the 
Kellaways Rock of Yorkshire — comparable with Paracepkalites — and the 
unnamed fragment from the Kellaways Rock of southwest England — 
comparable with Miccocephalites. On such comparison the date of the 
Fernie formation is later than the Combrash of England by some three 
or four hemerse — or even more. At any rate it comes into line 
with the Kellaways Rock, but possibly only with the earliest part 
of it. 
Miccocephalites , however, would appear to be a new addition to 
Macrocephalitid fauna. The small size of the examples suggests that they 
are catamorphs of the family and, therefore, that they may be expected 
late in the Macrocephalitid history. They may even indicate a time- 
episode which is new for the chronology of the Jurassic strata. 
The likeness of Miccocephalites to a series of species figured by Pom- 
peckj from Alaska (2), attributed to the genus Cadoceras , must not be 
overlooked. It may strengthen the chronological suggestion just made; 
but, as a preliminary, some consideration must be given to the affinities of 
Pompeckj’s forms. 
One species, Ammonites wosnessenskii, Grewingk (PI. IY. f. 1) Cado- 
ceras wosnessenski; Pompeckj (2, Pl. Y, f. 5), is a Cadoceratid, near to 
Cadoceras s. str. in suture-line and in mode of growth — increase of thick- 
ness being from 41 per cent at 27 mm. diameter to 56 per cent at 48 mm. 
(Pompeckj, p. 252). Another species, C . stenoloboide (Pl. VII, f. 2) is not 
Cadoceratid in suture-line, but, according to the figure, there is Cadoeera- 
tid increase of thickness: Pompeckj ’s text (p. 255), however, does not 
bear this out — be gives thickness as 36 per cent at 24*5 mm. diameter 
and as 37 per cent at 41 mm. However, it is not to these forms that the 
species of Miccocephalites bear resemblance—it is to the forms called 
Cadoceras catostoma (Pl. Y, f. 1), C. schmidti (Pl. Y, f. 2), C . grewingki 
(Pl. VI, f. 1), C. petelini (Pl. VI,' f. 4-6). 
There is special likeness of Miccocephalites laminatus to Cadoceras 
grewingki and as this is the closest resemblance a statement of difference 
will serve for all. In M. laminatus primary ribs are stronger and are 
more curved over the inner-marginal edge, the ribs are more decidedly 
laminate throughout, and the passage over venter is not so distinctly 
arcuate. 
The interest, however, is to determine the affinity of Pompeckj’s 
species; for, if they are closely allied, a similar date for the Alaskan and 
Canadian shells may, not unreasonably, be postulated, whereas if the 
likeness is merely deceptive no argument is to be founded upon it. 
Pompeckj ’s species, C. grewingki , etc., are not Cadoceras in a strict sense; 
they have more likeness to Pseudocadoceras and that is where comparison 
must be made; but they show no sign of the sharpened (fastigate) venter 
with arrow-like costae preceding their rounded stage: according to Pom- 
peckj ’s illustration (2, PL VI, f. Id) there is a continuous stage of rounded 
venter, whereas the thickness of whorl remains constant — ID per cent at 
32-3 mm. and at 37 mm. diameter for Cadoceras grewingki (Pompeckj, 
p. 259). These facts suggest that they are not Cadoceratids but are 
