INTRODUCTION xxvii 



is the ancient willow, Salix folaris, which now lives in the Arctic regions, and is found fossil in the Pleistocene beds 

 at Cromer and Bovey Traoey. 



Professor Huxley, in his lecture " On the Hypothesis of Evolution," in discussing the permanency of type, 

 remarks : " The progress of research has supplied far more striking examples of the long duration of specific forms 

 of Ufe than those which are furnished by the mummified ibises and crocodiles of Egypt. A remarkable case was 

 found in the neighbourhood of the Falls of Niagara. In the immediate vicinity of the whirlpool, and again upon 

 Goat Island, in the superficial deposits which cover the surface of the rocky subsoil in those regions, there are found 

 remains of animals in perfect preservation, and among them shells belonging to exactly the same species as those 

 which at present inhabit the still waters of Lake Erie . . We are fairly justified in concluding that no less a period 

 than 30,000 years hie passed since the shell-fish, whose remains are left in the beds to which I have referred, were 

 living creatures. 



" But there is still stronger evidence of the long duration of certain types. I have already stated that, as we 

 work our way through the great series of the Tertiary formations, we find many species of animals identical with 

 those which live at the present day — diminishing in numbers, it is true, but still existing, in a certain proportion, 

 in the oldest of the Tertiary rocks. Furthermore, when we examine the rocks of the Cretaceous epoch, we find 

 the remains of some animals which the closest scrutiny cannot show to be, in any important respect, different from 

 those which live at the present time. That is the case with one of the Cretaceous lamp-shells (Terebratula) which 

 has continued to exist unchanged, or with insignificant variations, down to the present day. . . Hence it must 

 be admitted that certain existing species of animals show no distinct sign of modification or transformation in the 

 course of a lapse of time as great as that which carries us back to the Cretaceous period ; and which, whatever its 

 absolute measure, is certainly vastly greater than thirty thousand years." ^ 



Sir J. Wilham Dawson in his " Geological History of Plants " (p. 110) conclusively shows that plants do not always 

 advance as time rolls on, but that they occasionally deteriorate, and even disappear. Thus he states that " the old 

 Cambrian and Silurian seas were tenanted with seaweeds not very dissimilar from those of the present time. 



" Ascending from the Brian to the Carboniferous System ... we are still within the hmit of the Palaeozoic 

 period and the reign of the gigantic club-mosses, cordaites, and taxine pines. At the close of the Brian there had 

 been over the whole northern hemisphere great changes of level, accompanied by active volcanic phenomena, and 

 under these influences the land flora seems to have much diminished. At length all the old Brian species had 

 become extinct, and their place was supphed by a meagre group of lycopods, ferns, and pines of different species 

 from those of the preceding Brian. This is the flora of the Lower Carboniferous Series. . . But the land again 

 subsided, and the period of the marine limestone of the Lower Carboniferous was introduced. In this the older flora 

 disappeared, and when the land emerged we find it covered with the rich flora of the coal formation proper, in which 

 the great tribes of the lycopods and cordaites attained their maxima, and the ferns were continued as before, though 

 under new generic and specific forms. There is something very striking in the succession of a new plant world without 

 any material advance." 



The curious and interesting aquatic plants known as Rhizocarps seem to have reached a climax in the Brian 

 age, since wliich time they have occupied an inferior position. 



The Lycopods " have long ago descended from their pristine eminence to a very humble place in nature." ^ The 

 ferns too have deteriorated, although " in the southern hemisphere at least they retain their arboreal dimensions 

 and ancient dominance." Similar remarks may be made of the Equisetacese, which in the older time formed con- 

 siderable sized trees. In the Brian forests the family of Cordaites flourished, but has long since perished. 



A question of considerable importance arises here in connection with the modern theory of the " Origin of Species 

 by Means of Natural Selection." This theory proceeds on the assumption that species are formed by modifications 

 and variations with an upward trend extending over long periods ; the modifications and variations conveniently 

 ceasing when a new species is formed — the species which was formed by fluctuation becoming somewhat suddenly 

 fixed and permanent. It may reasonably be urged that it is not possible or allowable to fix limits arbitrarily to 

 modifications and variations in plants and animals at any one stage, if these changes are taken for granted and 

 recognised at all previous stages : logically the changes with an upward trend must go on. In other words, if changes 

 are necessary to form a species, it is illogical to dispense with them when a certain point is reached, the causes which 

 produce the changes still existing. This circumstance of itself goes far to prove the necessity for types, or points 

 of departure for plants and animals ; types being central creations to which plants and animals recur or breed back 

 when they have strayed by variation under peculiar circumstances, accidental or otherwise. 



There would seem to be, not only types or central forms for plants and animals in the scheme of creation, but 

 also an arrangement whereby types, like individuals, grow, increase, and perfect themselves up to a certain point, 

 after which they cease to grow, diminish, deteriorate, and disappear. The great size and importance attained by 

 1 " Lectures and Essays by Thomas Henry Huxley " (Macmillan's series). Loudon, 1904 ; pages 22 and 23. ' Op. eit., p. 78. 



