THE EVIDENCE FROM MISSING LINKS. 151 



living beings are not supplied even to the extent he himself requires, 

 is answered in the expression of Mr. Darwin already quoted, namely, 

 " the imperfection of the geological record." No fact of geology is 

 more patent than that, to use Sir Charles Lyell's words, " it is not 

 part of the plan of Nature to write everywhere, and at all times, her 

 autobiographical memoirs. On the contrary," continues this late 

 distinguished scientist, " her annals are local and exceptional from 

 the first, and portions of them are afterwards ground into mud, sand, 

 and pebbles, to furnish materials for new strata," The very process 

 of rock-formation consists in the rearrangement of the particles of 

 previously formed materials, and the manufacture of new strata 

 implies the destruction of the old with the included " fossils " of the 

 latter. The geological series is thus certainly a detached and discon- 

 tinuous collection of formations, interrupted by gaps of considerable 

 and often undeterminable extent. Of the contemporaneous life-his- 

 tory of the globe, during the periods of time represented by such gaps, 

 we have no record whatever. But even when the materials for form- 

 ing a detailed history of any past period of our globe are found iii 

 tolerable plenty, the record is never complete. "We can never hope," 

 says Lyell in a most emphatic passage on breaks in the sequence of 

 rock formations, " to compile a consecutive history by gathering to- 

 gether monuments which were originally detached and scattered over 

 the globe. For, as the species of organic beings contemporaneously 

 inhabiting remote regions are distinct, the fossils of the first of several 

 periods which may be preserved in any one country, as in America, 

 for example, will have no connection with those of a second period 

 found in India, and will, therefore, no more enable us to trace the 

 signs of a gradual change in the living creation, than a fragment of 

 Chinese history will fill up a blank in the political annals of Europe." 

 Add to these considerations the brief chronicle of a long and 

 important chapter of geological history, namely, that soft -bodied 

 animals and plants are rarely preserved as fossils ; that land animals 

 are but sparsely represented in any formations as compared with 

 marine forms ; and that even " metamorphism," or the alteration of 

 rocks subsequent to their formation, is known to alter and obliterate 

 their fossil contents, and we find reasons of the most stable and 

 satisfactory kind for the imperfect nature of even the fullest records 

 of rocks and of their fossils that man has been able to obtain. 



But in what direction does the positive evidence we have been able 

 to obtain lead ? Clearly to the side of evolution, and towards the 

 supply of " missing links " in a fashion which even the most sanguine 

 expectations of scientific ardour could scarcely have hoped to see 

 realised. Bearing in mind that vast tracts of rock-formations are as yet 

 absolutely unexplored, the present subject is seen to be one to which 

 each year brings its quota of new and strange revelations. And at 



