134 TIME AND LIFE 



student of physical geology, who fully believes in the 

 uniformity of the general condition of the earth through 

 geologic time, may feel compelled by what he knows of 

 causation, and by the general analogy of nature, to suppose 

 that our solar system was once a nebulous mass, that 

 it gradually condensed, that it broke up into that wonderful 

 group of harmoniously rolling balls we call planets and 

 satellites, and that then each of these underwent its 

 appointed metamorphosis, until at last our own share of 

 the cosmic vapour passed into that condition in which 

 we first meet with definite records of its state, and in which 

 it has since, with comparatively little change, remained. 



The doctrine of uniformity and the doctrine of progression 

 are, therefore, perfectly consistent ; perhaps, indeed, they 

 might be shown to be necessarily connected with one 

 another. 



If, however, the condition of the world, which has 

 obtained throughout geologic time, is but the sequel to 

 a vast series of changes which took place in pregeologic 

 time, then it seems not unlikely that the duration of this 

 latter is to that of the former as the vast extent of geologic 

 time is to the length of the brief epoch we call the historical 

 period ; and that even the oldest rocks are records of an 

 epoch almost infinitely remote from that which could 

 have witnessed the first shaping of our globe. 



It is probable that no modern geologist would hesitate 

 to admit the general validity of these reasonings when 

 applied to the physics of his subject, whence it is the 

 more remarkable that the moment the question changes 

 from one of physics and chemistry to one of natural history, 

 scientific opinions and the popular prejudices, which 

 reflect them in a distorted form, undergo a sudden meta- 

 morphosis. Geologists and palaeontologists write about 

 the " beginning of life " and the " first-created forms of 

 living beings," as if they were the most familiar things in 

 the world ; and even cautious writers seem to be on quite 

 friendly terms with the " archetype " whereby the Creator 

 was guided " amidst the crash of falling worlds." Just as 

 it used to be imagined that the ancient universe was 

 physically opposed to the present, so it is still widely 

 assumed that the living population of our globe, whether 

 animal or vegetable, in the older epochs, exhibited forms 

 so strikingly contrasted with those which we see around 

 us, that there is hardly anything in common between the 



