414 Notices of Memoirs — British Association — 



sometimes degenerate into a jargon which is naturally repellent to an 

 educated mind. Nevertheless, I still hope to show that, with all 

 these difficulties, there is so much of fundamental interest in the new 

 work that it is worth while to make an effort to appreciate it. 



* iif * * * * * 



In this connexion it is necessary to combat the mistaken popular 

 belief that the main object of studying fossils is to discover the 

 ' missing links' in the chain of life. We are told that the idea of 

 organic evolution is not worthy of serious consideration until these 

 links, precise in character, are forthcoming in all directions. More- 

 over, the critics who express this opinion are not satisfied to consider 

 the simplest cases, such as are afforded by some of the lower grades of 

 ' shell-fish ' which live together in immense numbers and have limited 

 powers of locomotion. 



* *- * 1^ * * * 



They. even expect continual discoveries of links among the rarest of 

 all fossils, those of the higher apes and man. The geologist, on the 

 other hand, knowing well that he must remain satisfied with a know- 

 ledge of a few scattered episodes in the history of life which are 

 always revealed by the merest accident, marvels that the discovery of 

 * missing links ' is so constant a feature of his work. He is convinced 

 that, if circumstances were more favourable, he would be able to 

 satisfy the demand of the most exacting critic. He has found enough 

 continuous series among the moUusca, for example, and so many 

 suggestions of equally gradual series among the higher animals, that 

 he does not hesitate to believe without further evidence in a process 

 of descent with modification. 



A.mong these general features which have been made clear by the 

 latest systematic researches, I wish especially to emphasize the interest 

 and significance of the persistent progress of life to a higher plane, 

 which we observe during the successive geological periods. For 

 I think palseontologists are now generally agreed that there is some 

 principle underlying this progress much more fundamental than 

 chance-variation or response to environment, however much these 

 phenomena may have contributed to certain minor adaptations. Con- 

 sider the case of the backboned animals, for instance, which I happen 

 to have had special opportunities of studying. 



We are not likely ever to discover the actual ancestors of animals 

 on the backboned plan, because thej' do not seem to have acquired 

 any hard skeleton until the latter part of the Silurian period, when 

 fossils prove them to have been typical and fully developed, though 

 low in the backboned scale. The ingenious researches and reasoning 

 of Dr. W. H. Gaskell, however, have suggested the possibility that 

 these animals originated from some early relatives of the scorpions and 

 crustaceans. It is therefore of great interest to observe that the 

 Eurypterids and their allies, which occupy this zoological position, 

 were most abundant during the Silurian period, were represented by 

 species of the largest size immediately afterwards at the beginning of 

 the Devonian, and then gradually dwindled into insignificance. In 



