476 Reports and "Proceedings — 



as being greater than that of the shallow-water organisms of existing seas, 

 which were alone known. It is by no means clear, however, with our 

 present knowledge, that Pictet's supposed law holds good, and it will 

 require a considerable amount of work before it can be shown to be 

 even apparently true. Our lists of the fossils of different areas are not 

 sufficiently complete to allow us to generalize with safety, but a com- 

 parison of the faunas of Australia and Britain indicates a larger percentage 

 of forms common to the two areas, as we examine higher groups of the 

 geological column. If this indication be fully borne out by further work, 

 it will not prove the actual truth of the law, for the apparent wider 

 distribution of ancient forms of life might be due to the greater pro- 

 bability of elevation of ancient deep-sea sediments than of more modern 

 ones which have not been subjected to so many elevatory movements. 

 Still, if the law be apparently true, it is a matter of some importance 

 to geologists ; and I have touched upon the subject here in order once 

 again to emphasize the possibility of correlating comparatively small 

 thicknesses of strata in distant regions by their included organisms. 



Mention of Pictet's laws, one of which states that fossil animals were 

 constructed upon the same plan as existing ones, leads me to remark 

 upon the frequent assumption that certain fossils are closely related to 

 living groups, when the resemblance between the hard parts of the living 

 and extinct forms are only of the most general character. There is a 

 natural tendency to compare a fossil with its nearest living ally, but the 

 comparison has probably been often pushed too far, with the result that 

 biologists have frequently been led to look for the ancestors of one living 

 group exclusively amongst forms of life which are closely related to those 

 of another living group. The result of detailed work is to bring out 

 more and more prominently the very important differences between some 

 ancient forms and any living creature, and to throw doubts on certain 

 comparisons ; thus I find several of the well-known fossils of the Old 

 Red Sandstone, formerly referred without hesitation to the fishes, are 

 now doubtfully placed in that class. 



The importance of detailed observation in the field is becoming every 

 day more apparent, and the specialist who remains in his museum ex- 

 amining the collections amassed by the labours of others, and never 

 notes the mode of occurrence of fossils in the strata, will perhaps soon 

 be extinct, himself an illustration of the principle of the survival of the 

 fittest. In the first place, such a worker can never grasp the true 

 significance of the changes wrought on fossil relics after they have become 

 entombed in the strata, especially amongst those rocks which have been 

 subjected to profound earth-movements ; and it is to be feared that many 

 "species" are still retained in our fossil lists whose supposed specific 

 characters are due to distortion by pressure. But a point of greater 

 importance is, that one who confines his attention to museums cannot, 

 unless the information supplied to him be very full, distinguish the 

 differences between fossils which are variations from a contemporaneous 

 dominant form, such as " sports," and those which have been termed 

 " mutations," which existed at a later period than the forms which they 

 resemble. The value of the latter to those who are attempting to work 

 out phylogenies is obvious, and their nature can only be determined as the 

 result of very laborious and accurate field-work - ; but such labour in such 

 a cause is well worth performing. The student of phylogeu}* has had 

 sufficient warning of the dangers which beset his path, from au inspection 

 of the various phylogenetic trees, constructed mainly after study of 

 existing beings only, so 



"... like the horealis race, 

 That flit ere you can point their place " : 



