TJie American Geologist. 
July, 18'J2 
from the intitrix. A great part of the rest of the head still re- 
mains broken and bedded in the stone, and much time and great 
labor must be expended before we shall be in a position to fully 
describe this. No part of the body has been discovered. 
GORCONICHTHYS CLARKI 
EXPLANATION OF FIGURE. 
Lower left mandible of Gorgonirhthys clarki 25 iuches long, showing 
groove worn by premaxillarv, lateral process and denticles, and overlap 
of apparently two bones aokylosed together (mandibular and articular). 
Premaxillary tooth, broken, point onlj'. 
Lateral tooth, fitting against lateral process of mandible. 
Rone, exact nature uncertain, apparently a second lateral tooth in up- 
per jaw. 
Gorg'OnichthyS, g". n., Loicer jaw or numdlhle. 
1\\ general outline this resembles the corresponding bone of Di- 
nichtJii/s, from the largest species of which also it does not much 
differ in length, being in this — the only specimen yet known — 25 
inches long. There is the same upward curve at the hinder end, 
where also the bone thins away to a blade-like plate, the end of 
which was apparently received between two thin bony plates and 
afforded attachment for enormous muscles. The ankylosis of the 
two bones of which the jaw consists is firmer than in Dinirht/ii/.s; 
that is to sa}^, the jaw appears almost as if it consisted of only a 
single bone. 
A little ia front of the middle the mandible rises into a rounded 
tooth-like process an inch and a half high and occupying about 
four inches of its length. Each slope of this process is set with 
a row of five or six denticles or rather denticular serrations of the 
bone, standing at right angles to the surface. The resemblance 
of the fish in this point to Dtnichthys hertzeri of the so-called Hu- 
