TERRIBLE FISHES AND THEIR COMPANIONS. 183 



mu-cro-na'-ta) called "petrified butterflies" by the boys of the 

 vicinity. The deposit has been cut through by the Great 

 Western Kailway. The Hamilton strata are almost every- 

 where well stocked with the treasures of the ancient sea ; and 

 I have observed that the small and parasitic species are more 

 abundant than in other formations. The greater part of the 

 good fossils found in the Drift of the north-western states are 

 derived from this group. 



But after all, the most astonishing relics of the Devonian 

 Age are the fish-plates and fish-teeth found in the upper part 

 of the System. Some years ago, a German-American clergy- 

 man came to me with fine specimens of fossils from Ohio, 

 among which were teeth and jaws of fishes, which he had 

 laboriously worked out of concretions found in the vicinity of 

 Delaware, Ohio. The concretions were imbedded in shales 

 immediately above the Hamilton formation. This was Rev. 

 Hermann Hertzer ; and he urged with much persistence that 

 I undertake the description of the fossils. Knowing, however, 

 that Dr. J. S. Newberry was at work on fossil fishes, I finally 

 induced him to turn his fish-remains over to Dr. Newberry ; 

 and they now constitute a part of the palseontological collec- 

 tion of Columbia College. Dr. dewberry's description of these 

 and other Ohio fishes may be found in the first volume of the 

 Report on the Palaeontology of Ohio. The two principal genera 

 have been named Din-icti-thys (terrible fish) and As-pid-ich'-thys 

 (shield-fish). 



The cranium of Dinichthys was composed of thick bony 

 plates, strengthened with massive internal arches, and was at 

 least two feet in length and the same in breadth. The jaws 

 have on their margins, near the middle, a number of conical 

 teeth soldered to the bone not inserted in sockets and at the 

 front of each jaw, two strong, curved, triangular teeth, inter- 

 locking together. These teeth are shaped from the solid bony 

 tips of the jaws. The body was protected by bony plates which 

 on the back were large and thick. The body must have been 

 about three feet in diameter, and its length from fifteen to 

 twenty feet. Other fish remains of the same age, named 



