14 Sir diaries Lyell and Modern Geology. [Jan., 



contrary. But Sir Charles Lyell can claim the merit of having 

 foreseen the unstable nature of conclusions based on ignorance, for 

 in the first edition of the ' Principles' he contended that the 

 apparent breaks in the continuity of geological periods are due to 

 our imperfect information, and do not really exist in nature ; and 

 also that the organic remains imbedded in known deposits do not 

 represent the whole of the earth's inhabitants during those periods 

 or in those regions ; and he devoted some considerable space to the 

 illustration of these views, in contrast with the then prevalent 

 doctrine of catastrophes.* 



In those days Lamarck's hypothesis of progressive development 

 by transmutation of species excited a great deal of discussion ; as 

 also did the theory of the successive appearance on the earth's 

 surface of more and more highly organized animals and plants. In 

 support of the latter view, geologists appealed with alacrity to the 

 fossils discovered in different deposits as affording a positive proof 

 of its truth ; and they thus endeavoured to define the order of 

 nature, and to assign to each class of organisms the period of its 

 birth. But Sir Charles Lyell contended! that at that time there 

 was " no foundation in geological facts, for the popular theory of 

 the successive development of the animal and vegetable world, from 

 the simplest to the most perfect forms." And although subsequent 

 discoveries have abundantly justified Sir Charles Lyell's protest 

 against invoking negative evidence, to prove that this or that period 

 witnessed the creation of such or such a class of organisms, he has 

 at last admitted that the successive development theory is not much 

 affected by successive discoveries, and is probably necessary in the 

 present state of science.! It appears to us, however, not a little 

 mischievous, in so far as it encourages an appeal to negative 

 evidence, as was amusingly illustrated in 1851 by the late 

 Professor Edward Forbes, in reference to the discovery of Pul- 

 monifera in the Purbeck beds, "the (supposed) non-existence of 

 which during the Secondary epoch has called forth not a few 

 prematurely wise comments in geological works." 



" Agassiz just had given his bail, 

 'Twas adverse to creation, 

 That there should live pulmoniferous snail, 

 Before the chalk format ion."§ 



Since then Pulmonifera have been discovered in Carboniferous 

 deposits, and the history of nearly every group of animals contains 

 a record of similar premature conclusions and their subsequent 

 refutation. 



* See also his Presidental Address to the Geological Society in 1851, passim. 



f • Principles/ 1st edit, vol i., p. 153. 



X ' Antiquity of Man,' p. 405. 



§ Wilson and Geikie's ' Memoir of Edward Forbee,' p. 461. 



