416 . Dawson—Bearing of Devonian Botany, ete. 
of the Coal period, would, by permitting the extension of species 
over wide areas and fertile soils, and by removing the pressure 
previously existing, be eminently favorable to the production 
of new, and especially of improved, varieties. 
2. Whatever importance we may attach to the above supposed 
causes of change, we still require to account for the origin of our 
specific types. This may forever elude our observation, but we 
may at least hope to ascertain the external conditions favorable 
to their production. In order to attain even to this it will be 
types, or the reverse—whether these conditions were those of 
compression or expansion, or to what extent the a pearance of 
new types may be independent of any external conditions, other 
than those absolutely necessary for their existence. I am not 
without hope that the further study ‘of fossil plants may enable 
us thus to approach to a comprehension of the laws of the crea- 
tion, as distinguished from those of the continued existence of 
species. 
In the oo state of our knowledge we have no good 
ground eit: 
rence of such an advanced and ialized type as that of 
Syringoxylon, in the Middle Devonian, should guard us against 
these errors. The creative process have been applicable to 
grand 
ons which may not come till we have pr away, 
earnest and true to nature an its Creator, 
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