BIRDS OF THE ROCKS. 173 
some processes of progressive evolution, the 
fact does not conflict with my dream. It 
would seem that nature has often turned back 
from a partly accomplished purpose, as if upon 
discovering a shorter and better way, and it 
may be that the voices of nightingale and 
mocking-bird have not yet reached the perfec- 
tion belonging to some singer of zons ago. The 
syrinx of Archeopteryx may have been perfect, 
and yet the bird itself, with its cumbersome 
vertebrate appendage, may have been cast 
aside in order to begin another line of experi- 
ment, so to speak, in the direction of physical 
harmony. In such case the process would 
probably begin from the first again. It may 
appear that this really did take place ; for note 
that, after a vast geological space of time fol- 
lowing the extermination of the highly organ- 
ized Archaeopteryx, we see the lower orders 
caught in the grip of the rocks, as if nature 
were again toiling up, but by a different route, 
to reach the level of the oscznes, which appears 
to have been accomplished when the /adéo- 
spiza bella came forth in the tertiaryage. This 
species, buried in the shale amidst the insects 
upon which it used to feed, may be taken as a 
type of the fossil song-bird and should have 
been named simply AZelospiza, as the first of 
that genus and of the family Avznmgz/lide, just 
as we say, Adam or Eve! 
When we come to think of it, it is next to 
miraculous that any traces of the palzozoic 
birds are left to us at all. Can we well con- 
ceive how a sparrow or a blue-jay of our time 
shall be imprisoned in earth so as to be quar- 
ried out of a stone-bed some millions of years 
hence? Let us pause and reflect a moment 
