4 
it is at the present day, deta ils are sadly lacking. The occurrence and 
positions of Macrocephali , even in a country like England which has been 
geologically so much investigated, are known with very little precision. 
At how many horizons do the Macrocephali occur? It is very neces- 
sary to have exact information on this point and as to the chronology of 
Macrocephalitids before any attempt is made to deal with their geogra- 
phical distribution. Macrocephalites has been regarded as a fine example 
of wide distribution of an Ammonite genus — in other words that a deposit 
of a given date, characterized by yielding species of Macrocephalites , was 
not only laid down over a very large geographical area, but, what is more 
important, that this deposit has been preserved: it has not, like so many 
other deposits which were, perhaps, laid down over an area equally wide- 
spread, suffered from denudations both pene-contemporaneous and post- 
contemporaneous. It would be interesting to think of the Fernie forma- 
tion as a part of this widespread deposit and to draw a map showing its 
connexion with South America, the Arctic, Europe, Asia, and perhaps 
Australia; but it would be hazardous. There are not only the palaeonto- 
logical doubts as to generic and specific, not to mention possibly family, 
identity which have been referred to, but there are the geological doubts 
as to whether the species are found in one deposit or in various sequent 
deposits: both these engender chronological doubts as to whether the 
Macrocephali lived at one date or at several dates; and all these together 
produce doubts as to whether such a palseogeographicai map would be 
correct. For it makes all the difference if only one deposit or if several 
sequent deposits contain the species. In the first case there would be a 
phenomenon of stratal spread and preservation which is rather exceptional; 
in the second place there would be a phenomenon of the more usual type — 
limited spread of strata of each particular date because of pene-contempor- 
aneous erosions — an isolated patch of one date at one place, another iso- 
lated patch of a somewhat different date at another place, and so on, the 
whole spread having a false appearance of contemporaneity, first, because 
of stratigraphical position and, secondly, because of the general similarity 
in form of the contained ammonites; but when the suture-lines come to be 
thoroughly investigated it is to be expected that such likeness will be found 
to be more apparent than real. 
Sufficient has now been said to show that the questions that arise 
in connexion with a few specimens cannot with present knowledge be 
answered off-hand, for the investigation raises issues that are fairly 
complicated. But having said this much it is advisable to describe the 
Canadian specimens; afterwards it may be possible to supplement these 
remarks. 
A casual comparison of d‘Orbigny ? s figure of Ammonites macrocephalus 
(PI. CLI) and Zittel’s figure of Macrocephalites macrocephalus (p. 470, 
fig, 655) has given rise to the opinion, informally expressed in various 
quarters, that ZitteFs figure is a copy of d'Orbigny’s, in spite of the fact 
that Zittel says his specimen is from Ehningen. Blake, though not actually 
expressing this view, comes to the conclusion that they are the same 
species, as shown by his synonymy of Macrocephalites lypicus (p. 42). 
