90 ANNITERSAEY ADDEESS 



over and over again, to volcanic or metamorpliic action, and have 

 consequently been deprived of all traces of their organic contents. 

 But we can only take the data which our researches have enabled 

 us to procure ; and, until we have more complete information, we 

 have no right to endeavour to explain the " ignotiim per ignotius.'''' 

 Let us examine the organic contents of those formations which 

 appear to be the oldest in point of time. 



Having, as our present basis, the fact that the earliest fossiliferous 

 formation known to us is marine, it is useless to expect to discover 

 in that formation the original horse* or other land mammal. But 

 we do find in it among the marine organisms neither a less variety, 

 nor a lower degree of organisation, than at present exists in the 

 same classes and ordei's of the animal kingdom. 



In the Bohemian fossiliferous formation, called the Primordial 

 Zone by that experienced palaeontologist, M. Barrande, and corre- 

 sponding with our Cambrian rocks, he had found up to 1846 

 " twenty-six species of trilobites, all of them belonging to new 

 species, and the greater part of them to new genera" (Lyell's 

 ' Elements of Geology ' ). He spoke of this formation as occupying 

 " le meme horizon que les formations fossiliferes les plus anciennes 

 de Suede, de JSTorvege, et des lies Britanniques." At a later 

 period, 1856, Barrande stated that he had in his collection between 

 1400 and 1500 species of fossils from the Silurian and Primordial 

 rocks of Bohemia. These consisted of Mollusca, Crustacea, and 

 many other kinds of Invertebrata. Among them cephalopods are 

 the highest or most perfect forms of Mollusca, and allied to fishes. 

 The Cephalopoda, which were provided with external shells, e.g. 

 Nautili and allied forms, have left scarcely any surviving repre- 

 sentatives, although they abounded in the Palaeozoic epoch, and 

 comprised a very great number of orders, families, genera, and 

 species. 



" Tis as the gen'ral pulse 

 Of life stood still, and Nature made a pause, 

 An awful pause ! prophetic of the end ! " 



This, however, was the conception of a poet, not of a palaeonto- 

 logist ! The Brachiopods, Avhich constitute an aberiant group of 

 Mollusca, are entitled to even a greater claim of antiquity, being 



"of ancestry 



Mysteriously remote and high." 



Professor King says : "So far as is known, the second and highest 



* I am one of those who are not satisfied with the evidence adduced as to the 

 supposed progenitor of the hor.se, or Uippariou. See I'rofessor W. C. William- 

 sou's Lectures on ' The Succession of Life on the Earth,' 1877. 



