﻿SXviii PROCEEDINGS OF THE GEOLOGICAL SOCIETY, 



overrate the importance of that work to the geological student, or 

 the difficulty of its compilation, in arranging and comparing the 

 numerous organic remains described by different persons in different 

 places, and in giving due precedence to the numerous synonyms 

 "which have been introduced. 



In relation to his theoretical speculations on the plan of creation, 

 as deduced from geological data, and from the present state of the 

 natural world, I may in particular advert to his treatise entitled 

 ' Investigations of the Laws of Development of the Organic "World, 

 during the period of the Formation of the Earth's Surface,' to which 

 a prize was awarded in the year 1857 by the French Academy, — the 

 subjects proposed having been, " first, to examine i the laws of the 

 distribution of fossil organic bodies in the different sedimentary for- 

 mations, according to the order of their superposition; secondly, 

 to discuss the question of their successive or simultaneous appearance 

 or disappearance ; and thirdly, to inquire into the nature of the 

 relations between the existing state of the organic world and its 

 anterior states." In that remarkable work we are presented with a 

 series of tabular views, exhibiting the numerical distribution of 

 fossil genera and species, both of plants and animals, as they appear 

 in the successive stratified formations of the earth's crust, capable 

 of serving not only as statistical documents of the highest value to 

 illustrate a theory of the development of life, but also as a standard 

 to which future palaeontologists may refer when they desire to know 

 the point which their science has reached in our time. In the same 

 work the Professor has endeavoured to show that a progressive 

 advance towards the perfection of animal and vegetable forms and 

 attributes has kept pace with a parallel and equally gradual improve- 

 ment in the external conditions of life, or in the habitable state of 

 the globe. 



Professor Bronn supposes that there has been a passage from a 

 thalassic and insular to a continental state of the globe, in which 

 high mountain-chains and large areas of land separated by inter- 

 vening seas have been formed, and that during those changes a 

 contemporaneous development of the organic world has been going 

 on, from the most simple and imperfect to the more complex and 

 perfect — a progress equally , displayed by plants and animals, — the 

 acotyledonous, for example, having preceded the dicotyledonous 

 plants, and the marsupial mammaLs of the oolite having appeared 

 before the placental forms of the tertiary period. Tbis relation of 

 the continued improvement in the physical state of the earth and 

 the concomitant changes in organic life Professor Bronn calls the 

 tqrripetal law. "Without pretending to offer any opinion on these 

 difficult problems, to which my own studies have not been directed, 

 I. may observe that we should he lost in the contemplation of the 

 multiplicity of facts already accumulated respecting the past history 

 and present state of the organic and inorganic worlds, were they not 

 presented to us in a connected view by the aid of some such bold 

 and comprehensive theoretical speculations, which are the more 

 interesting when we consider their bearing on ^Ir. Darwin's views, 



