122 PALEOZOIC FISHES OF NORTH AMERICA. 
PLACODERMS. 
Dinichthys Terrelli, Newb., Cleveland shale, Ohio. 
Gouldii, Newb., Cleveland shale, Ohio. 
minor, Newb., Cleveland shale, Ohio. 
corrugatus, Newb., Cleveland shale, Ohio. 
intermedius, Newb., Cleveland shale, Ohio. 
curtus, Newb., Cleveland shale, Ohio. 
Titanichthys Agassizii, Newb., Cleveland shale, Ohio, 
Clarkii, Newb., Cleveland shale, Ohio. 
Diplognathus mirabilis, Newb., Cleveland shale, Ohio. 
Glyptaspis verrucosus, Newb., Cleveland shale, Ohio. 
Mylostoma Terrelli, Newb., Cleveland shale, Ohio. 
variabilis, Newb., Cleveland shale, Ohio, 
Trachosteus Clarkii, Newb., Cleveland shale, Ohio. 
A few facts of special interest in regard to the fishes of the Waverly 
deserve to be mentioned, viz: In the black shale at Vanceburgh, Ky., 
formerly worked for the artificial distillation of oil, a very interesting series 
of fish remains was obtained by Mr. Patterson, which are now in the State 
collection at Frankfort, Ky. Among these is the tail of a shark which must 
have been eight or ten feet long; the outline of the entire fish was traceable 
on the shale, but only this part was preserved. The tail is about a foot and 
a half long, and very heterocercal ; the vertebral column has entirely dis- 
appeared, and its place is marked by a smooth stripe between the spinous 
apophyses, which are plainly discernible. The rays of the lower lobe of 
the tail, nearly as large as one’s little finger, are thoroughly ossified. Asso- 
ciated with this impression, but not in immediate contact with it, were 
numerous spines of Cfenacanthus and teeth of Orodus, all of which probably 
belong together. 
A similar case of the ossification of the caudal fin-rays has been found 
by Dr. William Clark, at Berea, Ohio. Here the spines of Ctenacanthus 
Clarkii were so closely associated with the ossified fin-rays as to make it 
almost certain that they belong to the same fish, and the fins are connected 
with jaws which carry the teeth, called Cladodus Pattersoni. 
The geological level at Vanceburgh is essentially the same as at Berea, 
Ohio. Teeth of a small species of Cladodus (C Pattersoni) are very com- 
mon at both places, and at Vanceburgh a jaw was found which carries a 
large number of these teeth in place. They form many rows from front to 
rear (ten or more) and are nearly all of the same size, but some smaller ones 
