330 Life Changes on the Globe. 



and every trace of the previous creations of plants and animals 

 were destroyed, and replaced by a totally different set"* We snail 

 see how far this violence of expression is justified by Professor 

 Huxley's investigations ; but before dismissing the subject of 

 negative evidence, let us call to mind Sir C. Ly ell's remarks in 

 185I,f in reference to the dredging operations of Messrs. 

 Forbes and MacAndrew between the Isle of Portland and the 

 Land's End. During one hundred and forty dredgings, at va- 

 rious distances from the shore, they obtained a large quantity 

 of marine invertebrates, but very few traces of vertebrate life, 

 none of them referable to terrestrial animals. " If," says Sir 

 Charles, " reliance could be placed on negative evidence, we 

 might deduce from such facts, that no cetacea existed in the sea, 

 and no reptiles, birds, or quadrupeds on the neighbouring land." 

 In comparing the fauna and flora of the two periods, or of 

 two contemporaneous countries, the amount of agreement or 

 difference which an observer will trace must depend very much 

 upon the method he employs. If he is a profound believer in 

 certain systems of classification, he may affirm objects to be 

 totally distinct, or new creations, and so forth, while they are 

 closely allied; and if we consider the pernicious influence 

 of spasmodic theories in blinding the mind even to obvious 

 facts, it is consoling to find so great an authority as Professor 

 Huxley confirming opinions which are in conformity with the 

 most probable deductions from general science. He tell us that, 

 if we leave negative differences out of consideration, and regard 

 the fossil world in the broad spirit suggested by comparative 

 anatomy, we shall be struck with " the smallness of the total 

 change." Out of "two hundred known orders of plants, not 

 one is certainly known to exist exclusively in a fossil state. 

 The whole lapse of geological time has as yet not yielded a 

 single new ordinal type of vegetable structure." In the animal 

 world the change has been greater ; but still ' ' no fossil animal 

 is so distinct from those now living as to require to be arranged 

 even in a separate class from those which contain existing 

 forms. It is only when we come to the orders, which may be 

 roughly estimated at about a hundred and thirty, that we meet 

 with fossil animals so distinct from those now living as to 

 require orders from themselves; and these do not amount on 

 the most liberal estimate to more than about ten per cent, of 

 the whole." The Protozoa, it appears, have not lost any known 

 order, the Coclenterata but one, the rugose corals — the Mollusca 

 none, the Echinoderms three, and the Crustacea two, " making 

 altogether five for the great subkingdom of Annulosa. Among 

 vertebrates there is no ordinally distinct fossil fish : there is 



* Annals of Natural Uhlonj, Fcb.-1862, p. 144. 



t Quarterly Journal of the Geological Society, May 1851, p. 53. 



