PROFESS OB HUXLEY ON THE WAR-PATH. 789 



beset with, mystery. We talk glibly of aqueous deposit as the 

 physical origin of stratification; but we know little indeed of the 

 physical conditions under which this agency worked in early times. 

 The scientific naturalists of the Challenger Expedition report 

 as the result of their investigations that nowhere in the existing 

 world of waters have they found going on anywhere such deposits 

 as are necessary to account for the vast massive accumulations of 

 the Palaeozoic sandstones. 



Before such, mountains as those of the Cambrian formation on 

 the northwest coast of Scotland cut out of the thickness of ap- 

 parently one continuous deposit full of the ripple-marks of the 

 sea, and yet destitute of life the theoretical uniformitarian may 

 well stand abashed. Similar difficulties are crowded into the con- 

 ditions under which our great storages of carbon were provided 

 for by repeated elevations and depressions of the land, each eleva- 

 tion giving occasion for the growth of a dense and rich vegeta- 

 tion ; and each depression potting it up and preserving it for 

 future use. Similar difficulties beset the equally massive lime- 

 stone formations of the Secondary rocks. But even these diffi- 

 culties are less serious and less profound than those which beset 

 the progress of organic life. Only, in this case there are some 

 great outlines which are clear and definite. We can see that or- 

 ganic life has advanced from less to more from low to higher 

 levels from the generalized to the specialized, and from various 

 functions performed roughly by some one rude and simple mech- 

 anism, to the same functions separated, elevated, and committed 

 to the care of selected and adapted organs. We can see how there 

 is some strange but profound analogy between this magnificent 

 line of march and that along which every living creature goes in 

 its individual growth. Just as the science of embryology has in 

 in some measure revealed to us how that is, in what order " the 

 bones do grow in the womb of her that is with child," so in the 

 embryology of this planet, as revealed to us in the rocks, we can 

 see the steps of a process which is not only analogous but homolo- 

 gous. That is to say, the two pathways are not only vaguely like 

 each, other according to some dim resemblance, but are identical 

 as corresponding parts in one plan, and of one intellectual method. 

 We can see that the past ages were full of prophetic germs. We 

 can see the rise, one after another, of structures which were in- 

 cipient, useless, or comparatively useless for a time, but destined 

 in the future for some splendid service. Our physiologists, and 

 anatomists, and morphologists are wholly unable to resist this 

 evidence when it is their business to describe the facts. The 

 structure of their own mind compels them to admit it, even when 

 they struggle hard to shut their eyes against it. 



Few men have used language more expressive of conceptions 



TOL. XXXVIII. 55 



