Brontichthys clarki^from the Cleveland shale. — Claypole. 379 
cur in intimate association with the granitoid gneisses and in 
some cases appear to be interbedded with them. 
Whether the other ciystalline limestones of New Jersey are 
of the same age as those of Warren county, has not been 
proved. The answer has generally been that they are. This 
seems to be the most probable view. If the}' are, and if the 
position taken in the present paper is valid, then the eiwstal- 
line limestones of Sussex county, and of other places in New 
Jersey, would also be, as they have generally been supposed 
to be, of pre-Cambrian or Archaean age. 
[PaL.EONTOLOGICAL Nc ITES FROM BlCHTEL COLLEGE.— NO. 8.]. 
ON A NEW PLACODERM, BRONTICHTHYS GLABKI, 
FROM THE CLEVELAND SHALE. 
By E. W. Claypole, Akron. Ohio. 
(Plate XII.) 
To the three great placoderms of the Upper Devonian of 
Ohio, Dinichthys, Titanichthys, and Gorgonichthys, must now 
be added a fourth genus not less remarkable than the rest and 
only less striking because it is not the first. In the Cleveland 
shale of Cuyahoga county Dr. Clark has recently found a jaw, 
which, while bearing a strong general resemblance to Titan- 
ichthys, yet differs so much that it cannot be placed in that 
genus. Two views of the fossil given herewith will illustrate 
its characters. 
Only a single ramus, the left, was found, and most careful 
and continuous search failed to discover its mate. It is slightly 
imperfect on the hinder end but almost complete in front. It 
must originally have measured at least twenty-five inches from 
end to end. Its greatest depth toward the spatularend is five 
inches. In this part it shows no distinction from the jaw of 
Titaniehthj's. But in front its construction is much more 
massive. It bends outward about five inches from the tip, 
and at the bend begins a deep alveolus resembling that in the 
jaw of Titanichthys but growing deeper toward the end. This 
alveolus is now an inch and a half deep, and when its walls 
were entire it must have been Bomewhat deeper. The inner 
wall is rather higher and thicker than the other. It is ;ippa- 
