354 
POPULAR SCIENCE REVIEW. 
FOSSIL BIRDS. 
BY S. J. MACKIE, E.G.S. (EDITOR OF “THE GEOLOGIST.”) 
O F all the wonderful applications of vital force as a mecha- 
nical power to the locomotion of solid bodies, that 
of flight is the most marvellous ; and delighted as we are 
with the cheerful voices and painted plumage of birds, their 
graceful and rapid motions through the ah’ equally attract our 
attention. 
In the far past exhibited by Geology, we look back to a 
pristine age of shell-fish and “ creeping things.” Then follow 
fishes, smoothly gliding through the sea — nicely-balanced 
aquatic balloons that rise and fall by voluntary compression or 
expansion, and propel themselves by the strokes of side- 
paddles or the lateral lashings of a rudder-like tail. Next, 
amphibious life — great reptiles basking in the sea, and slug- 
gishly crawling over the muddy shores. Then, an age of mam- 
mals — browsing herbivores, fierce carnivora, flat-footed bears, 
ponderous elephants, fleet deer and horses — walking on four 
props or legs on the firm land. Now we see four-handed beasts 
swinging with easy agility from bough to bough, and tree to 
tree — vegetarian inhabitants of the woods — and two-footed, 
two-handed man walking erect, and master of the earth. 
From the earhest records of the earth’s history that we pos- 
sess, the idea of flight seems absent ; and it is not until we 
have passed the vast Paheozoic age, and entered the secondary 
epoch of the earth’s crust-formation, that we find any trace of 
this idea. Then, indeed, we find foot-prints of perhaps wing- 
less, or nearly wingless, birds ; but scarce a bony relic of all 
the thousands that trampled on the yielding shore, and left 
“ their foot-prints on the sands of time.” The first of birds, 
so far as we can learn from their foot-prints, were cursorial — 
runners like the ostrich, or rather like the rhea. We have no 
evidence to show they could accomplish long- or lofty flights ; 
but, on the contrary, all the little that we know seems to prove 
that their wings were rudimentary, and only assistant to their 
velocity of pedal progression. 
Then follows a long silence, broken, as it were, by whispers, 
and a few decisive words — a few bones, here and there, in the 
cretaceous and oolitic beds — and then the wonderful Archasop- 
eryx. But during this long silence flight was a prominent 
feature of animal motion; and that, too, in perhaps its most 
