THE TESTIMONY OF THE ROCKS. 51 
Sandstone, one of the most extraordinary, and the one 
in which Lamarck would have most delighted, is the 
Pterichtys, or winged fish. Had Lamarck been the dis- 
coverer, he would unquestionably have held that he had 
caught a fish almost in the act of wishing itself into a 
bird. Here are wings which lack only feathers, a body 
which seems to have been as well adapted for passing 
through the air as the water and a tail by which to 
steer. I fain wish I could communicate to the reader 
the feeling with which I contemplated my first-found 
specimen. It opened with a single blow of the hammer; 
and there on a ground of light-colored limestone, lay the 
effigy of a creature fashioned apparently out of jet, with 
a body covered with plates, two powerful-looking arms 
articulated at the shoulders, a head as entirely lost in the 
trunk as that of the ray or the sun-fish, and long angular 
tail.” Miller says that he at first thought he had dis- 
covered a kind of turtle that partook of the characteristics 
of a fish. But he continues: “I had inferred somewhat 
too hurriedly, though perhaps naturally enough, that these 
wings or arms, with their strong sharp points and oar- 
like blades, had been at once paddles and spears, — in- 
strument of motion and weapons of defence; and hence 
the mistake of connecting the creature with the Chelonia 
(turtles). I am informed by Agassiz, however, that they 
were weapons of defence only, which, like the spines of 
the river bull-head, were erected in moments of danger 
or alarm, and at other times lay close by the creature’s 
side; and that the sole instrument of motion was in the 
tail. The river bull-head, when attacked by an enemy, 
or immediately as it feels the hook in its jaws, erects 
its two spines at nearly right angles with the plates of 
the head, as if to render itself as difficult of being 
swallowed as possible. The attitude is one of danger 
