64 PALEOZOIC FISHES OF NORTH AMERICA. 
niferous limestone, plainly a marine and relatively deep-water sediment, 
while the Old Red Sandstone, which had furnished most of the fossils found 
abroad, was probably a lake deposit. The fifteen years which have elapsed 
since the publication of my former review have confirmed the conclusion 
then reached, but have compelled me to modify some of my statements of 
act; for not only has a fresh-water fish fauna been discovered in Canada 
which closely resembles that of the foreign Old Red Sandstone, but in the 
marine limestone of Germany Dinichthys, Aspidichthys, Macropetalichthys 
and Macheracanthus have now been obtained, so that the discrepancy be- 
tween the European and American Devonian fish faunas has ceased to exist 
by the discovery in each country of similar fossils in similar deposits. 
DinicutHys Herrzerr, Newb. 
Plate XXXII, Fig. 2. 
Dinichthys Hertzeri, Newb., Paleontology of Ohio, vol. 1, p. 316, pls. 30-37. 
In the first and second volumes of the Palzeontology of Ohio the two 
largest and first-found species of Dinichthys are so fully illustrated, that they 
require no detailed description here. Of Dinichthys Hertzeri, from the Huron 
shale, we have no more new material. The Rev. H. Hertzer, who first dis- 
covered the species at Delaware, Ohio, and who cultivated that field with 
so much enthusiasm and success, changed his residence, and the exposures 
of the Huron shale in central Ohio have been of late neglected. On the 
Huron River, in Erie County, and in the valleys of the Scioto and many 
of its tributaries in southern Ohio, the formation is very extensively opened, 
and we have proof that it everywhere contains calcareous concretions within 
which are bones, but no one has been favorably located for collecting in 
these districts. 
There are some important points in the anatomy of this species of Di- 
nichthys of which we are still ignorant. The head, with its complete denti- 
tion and the dorsomedian plate, we have, but the defenses of the under side 
of the body have never been clearly made out. I have seen in some of the 
concretions broken open by Mr. Hertzer at Delaware traces of a plate 
nearly two feet in diameter, which does not correspond to anything known 
