GENERAL CONCLUSIONS. 
20 S 
Another deduction, equally apparent on 
an inspection of the fossils is, that the same 
conditions of life existed during their sea¬ 
son of vitality as prevail at present,"^ In 
all the elements of vegetable existence, 
the phenomena indicate identical supphes 
of light, air, and nutriment, and similar 
physiological and physical arrangements to 
those which are in active play around us 
now. Wherever we obtain a fragment of 
hard wood, we discern in it annular lines 
of growth; the fallen cones of the coal 
measures, the thickly strewn floors of ter¬ 
tiary lakes, remind us of the autumnal 
effects in modern woodlands, when the 
forest fruits are detached; 
“ Thick as autumnal leaves that strow the brooks 
In Vallombrosa.” 
Some of the consequences of this argu¬ 
ment may be stated in the words of Dr. 
Harris. 
* There is nothing, however, to forbid the supposition that 
during the carboniferous epoch a greater amount of carbonic 
acid was diffused than exists at present. Such an effect (within 
certain limits) whilst prejudicial to air-breathing animals, would 
be favourable to the rapid growth of vegetation. 
