JURASSIC AMMONOIDEA 
By S . S. Buckman, Southfield , England 
CONTENTS 
Page 
Introduction .. , 1 
P&Iseotitology 6 
Description of Canadian species 6 
Descriptions of two comparable English species 16 
Graphic comparison of genera and species 18 
Palaeontological synopsis 21 
Geographical distribution 21 
Chronology 22 
Bibliography 25 
Postscript 26 
Illustrations 
Plates I-III. Illustrations of fossils .109-113 
Figure 1. Graphic illustration of proportions of Macrocephalitids and Cadocerates 19 
INTRODUCTION 
Two ammonites from the Fernie formation of Blairmore were sub- 
mitted for identification by the Palaeontological Division of the Geological 
Survey, Canada. I expressed the opinion that they were of Macrocephalites 
aspect, indicating that the Fernie formation was of about the same date 
as the highest part of the Cornbrash of England ( macrocephalus hemera), 
but that further investigation, particularly in regard to suture-line, was 
necessary before the exact conclusion could be reached. Experience has 
shown the need for caution about like forms, especially those from distant 
areas: forms may masquerade under the guise of external similarity to 
European species and yet may possess internal differences which convict 
them of belonging to lineages of quite distinct origin. Literature is strewn 
with incorrect identifications, the result of reliance on external similarity: 
it is undesirable to add to them. Subsequently, six more specimens from 
the same locality and formation were forwarded to me with the request for 
a full investigation. 
Such an investigation would appear to be, and should be, quite simple, 
seeing how much work has been done on Macrocephalites, including Macro- 
cephalitoids , of Europe and of other parts of the world; but, in reality, it is 
complicated. Many investigations Have not been built on sure founda- 
tions, essential characters have been ignored or overlooked; as a conse- 
quence the elaborate superstructures that have been reared come crumbling 
to pieces almost at a touch. For, obviously, if these Fernie ammonites 
have a Macroeephalitic aspect, the first question to be asked of prior 
workers is, what is the genotype of Macrocephalites exactly? 
Fortunately the genotype is defined with some precision; it was not 
left, as formerly it was very frequently and often still is even at the present 
day, unsettled among a crowd of like species, without any indication to 
guide a subsequent worker choosing a genolectotype. This task should 
