=e — 
C.—GEOLOGY. 97 
fossils at certain horizons and their relative scarcity at others? Since 
such work has too often unfortunately been carried out in the museum 
or laboratory by workers unacquainted with the fossils in their natural 
environment, it is liable to fail to take note of peculiarities of preserva- 
tion and condition that may be significant, and new names have in the 
past been sometimes given to the same fossil in different conditions of 
preservation, or to other forms which owe their apparent peculiarities 
to the deformation of the rocks in which they lie. As is perfectly well 
known, the older rocks of this country have almost always suffered 
more or less considerably in this respect, though in the case of some 
rocks, such as mudstones, it is exceedingly difficult to estimate the 
degree of such deformation in hand specimens removed from their 
proper surroundings. So, too, the relative sizes of fossils may take on a 
totally new aspect when seen in the field. In such a connection we 
may note the characters of the Caradocian faunas of Shropshire and 
North Wales respectively. Similar fossils from. the two areas differ 
so much in size that the existence of small Welsh varieties is inevitably 
suggested, until it is realised when the faunas are seen in the field that 
the whole Welsh fauna is of smaller size though otherwise very similar, 
therefore obviously we are here dealing not with any true varieties but 
rather with a whole fauna living under less favourable conditions. 
The pity of it is that, in spite of all the labour and skill that has been 
expended, we are still left so largely in ignorance of the crucial facts 
that in these days we want to know. There is a very real need at the 
present time for the co-ordination of these descriptions so far as possible 
on genetic lines. The difference between the past and future paleonto- 
logical work appears to me to be just this: the older type of work is 
too dead, whilst the paleontology of the future must be essentially 
alive; it’ must vitalise fossil organisms, and regard them as parts of 
once-living’ entities possessing definite ancestors and descendants, 
developing along definite lines which are the result partly of internal and 
partly of external forces.* The biologist will find his interest in the 
degree of relationship between species-group and species-group, or in 
the precise relationship between ancestor and descendants within the 
species-group, but the value of the work to the geologist will lie rather 
in the determination of the definite lines along which evolution takes 
place and the horizons at which important and easily recognised evolu- 
tional stages are reached.’ 
It may perhaps be argued that the geological record is so imperfect 
that our story can at the best be of little value, because it will be so 
incomplete; to that I would reply that such features as have been 
sufficiently permanent in any organism to impress themselves upon the 
hard parts that are all that remain to us are likely to ‘be those of 
enduring significance, and therefore particularly reliable so far as they 
go. We may miss detail, but the main facts of the story should be 
beyond question. Up to the present time resemblances and differences 
existing between certain fossils have often been noticed as points to 
render identification. more accurate, but their true significance has too 
* Lang, loc. cit. 
12 
