2 Proceedings of the Royal Physical Society, 



Silurian period, though every plant and animal would be 

 new to us, we should find nothing in the structure or 

 development of the organisms at variance with the recognised 

 principles on which the living world of to-day has been 

 constructed. 



To the study of fossil organisms a distinctive name — 

 Palaeontology — has been given, as if it were a separate and 

 independent science. The term is undoubtedly a convenient 

 one, but its adoption has been in certain respects unfortunate, 

 inasmuch as it has tended to foster an impression that there 

 is some essential difference between living and extinct forms 

 of life. The palaeontologist, however, can make no satis- 

 factory progress in his special field of research, except in so 

 far as he is equipped with a knowledge of existing organisms. 

 This may seem a truism, yet it has not always been the 

 principle on which palseontological work has been carried on. 

 But if an acquaintance with the structure, habits, and growth 

 of living plants and animals is essential for the proper 

 understanding of the biological relations of extinct forms, 

 not less imperative is the necessity that all geological 

 speculations, based wholly or partly upon the evidence of 

 fossil organisms, should proceed upon the fullest attainable 

 information regarding the part played by the representatives 

 of these organisms at the present day. We need to study 

 the sources of their food, their peculiarities of habitat, their 

 geographical distribution with the causes that affect it, their 

 conditions of environment, the influences that favour or 

 retard their vigorous growth, their relations to the flora and 

 fauna of which they form a part, how their remains may be 

 imbedded in modern deposits, and whether these remains 

 ever accumulate in sufficient mass to take a noteworthy 

 place among the rock-forming materials of the globe. 



I cannot but think that one of the most pregnant results 

 of the deep-sea researches of recent years, is the large 

 treasure of fresh information that has been obtained for the 

 solution of such questions as these. Both the positive data, 

 which have been gathered in such abundance, and the 

 negative data, which are hardly less suggestive, furnish a 

 mass of evidence for geological investigation, and place us in 



