214 GEOLOGY OF OHIO. 
the mouth of Black River, and at the mouth of the Vermilion. In the 
former locality it is brought up in a fold of the strata to which allusion 
has already been made. About fifty feet of the extreme summit of the 
formation are here exposed, consisting of bands of black bituminous 
shale, interstratified with gray shale and thin sheets of micaceous, pearly 
sardstone. In the valley of the Huron, as generally farther south, it is 
a nearly homogeneous black shale. Although showing such limited ex- 
posures in the limits of Lorain county, the Huron shale has furnished 
some of the most interesting and extraordinary fossils that have ever 
been discovered. These are chiefly the remains of gigantic fishes, sim- 
ilar in character to some of those described by Hugh Miller, but very 
much larger. Most of the specimens obtained are referable toa single 
species of the genus Dinichthys, which will be found fully described in 
the paleontological portion of this report. The remains of Dinachthys 
were first found by the Rev. H. Hertzer in calcareous concretions at the 
base of the Huron shale, near Delaware, Ohio, and the species to which 
they belong—named in honor of the discoverer—is figured and described 
in Vol. I., Part Il., p. 316, plates 830and 31. Subsequently Mr. J. Terrell, of 
Sheffield, and Prof. G. N. Allen, of Oberlin, found on the lake beach, west 
of Avon Point, rolled fragments of large bones, which I recognized as 
portions of the great dorsal shield of Dinichthys. The finding of these 
Specimens prompted a search for the bones in place in the cliff of Huron 
shale from which they had evidently been washed out. This search was 
rewarded with very interesting results. Prof. Allen obtained by exca- 
vating the rock a complete dorsal shield some sixteen inches in diame- 
ter; and later, in company with Mr. G. K. Gilbert, a supra-scapular and 
a large pre-maxillary tooth. But the most interesting specimens found 
in this locality have rewarded the laborious and intelligent search of Mr. 
J. Terrell, the proprietor of the Lake Breeze House, situated in the imme- 
diate vicinity of the outcrop of the fish-bearing stratum. His first im- 
portant discoveries were those of an entire dorsal plate and the posterior 
half of a cranium, both of which are figured on plates 32 and 33 of our 
first volume. Unfortunately, these speciments were destroyed in the 
burning of Ely’s block in Elyria. Their loss has, however, been more 
than made good by Mr. Terrell, who has since discovered nearly the en- 
tire bony structure of an individual of gigantic dimensions, of which a 
more detailed description will be found in Part II. of this volume. This 
proves to be a distinct species from that found at Delaware at the base of 
the formation. The latter has a row of conical teeth on the edge of the 
maxillary, and a corresponding row with which these interlocked in the 
middle of the mandible, while in the Sheffield species, to which I have 
