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Show 264 . IMPERFECTION OF THE [CHAP. IX. · . th h perhaps extremely state, in a nearly uniform, .~f! to the principles fol-slight degree, they would, lacc?It b~ ranked as new and lowed by many palreonto ogis s, distinct species. d ree of truth in these re- If then, there b~ some eg t to find in our geologimarks, we have no ng~t to exbpecof those fine transitional cal formati·o ns, an I' nfinhi.t e num seurr edly have connecte d al l forms, w h. h my t eory as · t lC on . f the same group In o one the past and pre~ent ~~Ciesf ffe We ought only to look long and branching c ain o tos.el some more distantly for a few links, some mo~e t~~se t~ks let them be ever related t~ each ~t}:ul;iiff~~ent sta.,.es of the same fo~at~on, so close, If foun In li t. logists be ranked as distinct wou~d, by most pa n~~n ~etend that I should eve; have speCies. But I do p rd of the mutations of hfe, the suspected how poor a :eco tion resented, had not the best preserved geolo~~cal se~ng in~umerable transitional difficulty of our not IS~oven . h a eared at the com-lmineknsc ebmetewnte eann dt hcl eo ssep eof cieea~c h~~~matt! ' pressed so hardly on 1ny theory. . On the sudden appearance q-.;+ ' wlhwilceh gwrhooulpes gorof uAplsl ieodf Specjes.-The ab~pt ~ra~e~e~~ain formations, has be~n speCieS suddenly a)pe t 1 . ts for instance by Agassiz, urged by several pa reon o ogr_: ' 'bl than by Professor P . t d by none more 10re1 Y . . wte ' an 1 b. t. to the behef In the transSedgwick, as a fa~a o ~~c ~!erous s ecies, belonging to mutation of speCies.£ If.l ?- have re~lly started into life the same genera or ami {~s,be fatal to the theory of deall at o~lCe, the fact drfiuation through natural selecti?n. scent with slow mo c of forms all of whwh For the development of a ,group ·t ' must have have descende d f rom som e one progedn it hoer, progenitors been an extremel Y sl ow pro£c esst h· a· n modified descend-must have lived lo~g a1fs be ore te e;~e perfection of the ants. But we continua y ov~r-ra because certain g.enera geological record, and ~alsel~ lnf~ ~ithin a certain stage, tohr afta t1hneilyie ds idh anvoet enxo~is t beeel~o re0 ~ha t stage . We continually CHAP. IX.] GEOLOGICAL RECORD. 265 forget how large the world is, compared with the area over which our geological formations have been carefully examined; we forget that groups of species may elsewhere have long existed and have slowly multiplied before they invaded the ancient archipelagoes of Europe and of the United States. We do not make due allowance for the enormous intervals of time, which have probably elapsed between our consecutive formations,-longer perhaps in some cases than the time required for the accumulation of each formation. These intervals will have given time for the multiplication of species from some one or some few parent-forms ; and in the succeeding formation such species will appear as if suddenly created. I may here recall a remark formerly made, namely that it might require a long succession of ages to adapt an organism to some new and peculiar line of life, for instance to fly through the air; but that when this had been. effected, and a few species had thus acquired a great advantage over other organisms, a co1nparatively short time would be necessary to produce many divergent forms, which would be able to spread rapidly and widely throughout the world. I will now give a few examples to illustrate these remarks ; and to show how liable we are to error in supposing that whole groups of species have suddenly been produced. I may recall the well-known fact that in geological treatises, published not many years ago, the great class of mammals was always spoken of as having abruptly come in at the commencement of the tertiary series. And now one of the richest known accumulations of fossil mammals belongs to the middle of the secondary series ; and one true mammal has been discovered in the new red sandstone at nearly the commencement of this great series. Cuvier used to urge that no monkey occurred in any tertiary stratum ; but now extinct species have been discovered in India, South America, and in Europe, even as far back as the eocene stage. The most striking case, however, is that of the Whale family; as these animals have huge bones, are marine, and range over the world, the fact of not a single bone of a whale having been dis- 12 |