308 CONCLUSION 



we find the Mammalian type exhibiting the greatest divergence 

 from previously-existing forms ; first, by the appearance of 

 innumerable, huge Mastodons, Megatheriums, and other unwieldy 

 denizens of the ancient forests and plains ; and subsequently, by 

 the gi-adual modification of one of the ramifications of the Quad- 

 rumanous order, into those beings from whom primaeval Man 

 himself seems to have been evolved. 



These several types of life, however, which have from time to 

 time become more and more specialised, need not in any sense 

 represent the members of one progressive series. They may be 

 rather the products of different evolutional processes — divergencies, 

 taking place now in one direction and now in another, though 

 reproducing fundamentally similar types of organisation. The 

 lack of synchrony in the formation of similar fossils to which 

 Huxley called attention, and their separation often by vast periods 

 of time, might thus be in a measure explained. 



Our knowledge of the various living forms which have existed 

 in past ages is still of the most fragmentary character. Such as it 

 is, however, the record seems to show very plainly that there has 

 been nothing approaching to a continuous progression terminating 

 in the Mammalian type. Vertebrata in the form of fishes, as high 

 as any existing at the present day, have been in existence since the 

 time when the upper Silurian rocks were deposited. While at 

 different intervening periods in the earth's history, now one, now 

 another of the invertebrate forms of life have been in the as- 

 cendant, associated, perhaps, with representatives of some highly 

 developed and divergent branch of the vertebrate tree. Till at last 

 — as it were accidentally — at the summit of one of these diverging 

 branches, some of the branchlets pertaining to the quadrumanous 

 order began to undergo modifications which terminated in the 

 evolution of the immediate ancestors of the primaeval representa- 

 tives of our race. 



It is, therefore, needless to regard all preceding forms of life as 

 belonging to types lower than our own, or to suppose that they 

 have been the necessary precursors of our advent. 



There is indeed no small amount of evidence, deducible from 

 the history of the life of the globe antecedent to the advent of 

 Man, tending to prove that many of the above-mentioned develop- 

 mental divergencies cannot be regarded as constituting so many 

 necessary preliminary series. The palaeontological records, so far 

 as they have been discovered, would rather encourage a belief that 



