152 THE GEOLOGICAL MIDDLE AGE. 
been smaller than the hind ones. Some of the 
tracks show four toes all turned forward, while 
in others three toes are turned forward and one 
backward. It happened that the first tracks 
found belonged to the latter class ; and they very 
naturally gave rise to the idea that these impres- 
sions were made by birds, on account of this for- 
mation of the foot. This, however, is a mere in- 
ference ; and since the inductive method is the 
only true one in science, it seems to me that we 
should turn to the facts we have in our possession 
foi the explanation of these mysterious footprints, 
lather than endeavor to supply by assumption 
those which we have not. As there are no bones 
found in connection with these tracks, the only 
way to arrive at their true character, in the pre- 
sent state of our knowledge, is by comparing 
them with bones found in other localities in the 
deposits of the same period in the world’s history. 
Now there have never been found in the Trias 
any remains of Birds, while it contains innumer- 
able bones of Reptiles ; and therefore I think that 
we shall eventually find the solution of this mys- 
tery in the latter class. 
It is true that the bones of the Triassic Reptiles 
are scattered and disconnected ; * no complete 
skeleton has yet been discovered, nor has any foot 
* See the Investigations of Hermann von Meyer on Triassic 
Reptiles. 
