76 ANIMALS OF THE PAST 
of departure from other vertebrates, is yet to be | 
discovered ; at one time it was considered that _ 
they were the direct descendants of Dinosaurs, — 
or that at least both were derived from the — 
same parent forms, and while that view was 
almost abandoned, it is again being brought for- 
ward with much to support it. It has also been © 
thought that birds and those flying reptiles, the 
pterodactyls, have had a common ancestry, and 
the possibility of this is still entertained. Be — 
that as it may, it is safe to consider that back — 
in the past, earlier than the Jurassic, were creat- 
ures neither bird nor reptile, but possessing 
rudimentary feathers and having the promise — 
of a wing in the structure of their fore legs, — 
and some time one of these animals may come — 
to light ; until then Archzopteryx remains the © 
earliest known bird. 
In the Jurassic, then, when the Dinosaurs © 
were the lords of the earth and small mammals — 
just beginning to appear, we come upon traces _ 
of full-fledged birds. The first intimation of | 
their presence was the imprint of a single feather — 
found in that ancient treasure-house, the Solen- © 
hofen quarries; but as Hercules was revealed — 
