124 PALEOZOIC FISHES OF NORTH AMERICA. 
perhaps the finest of the genus. It is described and figured in another part 
of this memoir, and is named Ct. Wagneri, after its discoverer. 
In the valleys of Rocky, Black, and Vermilion Rivers, ail of which 
enter Lake Erie west of Cleveland, the Waverly rocks are freely opened. 
Rocky River, draining the Conglomerate area of central Medina County 
with its upper branches, and having its mouth in the Erie shale, cuts through 
the entire Waverly formation. Fish remains have been revealed at many 
levels in this section, and some of special interest. At the top of the Wav- 
erly at Medina, Bagdad, and Royalton we find three species of Gyracanthus, 
the only ones yet met with in the United States (C. Alleni, C. compressus, 
and C. inornatus.*) 
These are the pectoral spines of sharks, and were often used for crawl- 
ing over shallows and shores, as we know by their worn condition; the 
young ones being perfect and acute, the older ones, which should have 
been nearly two feet in length, reduced to mere stumps, with every inter- 
mediate grade. All the spines of Gyracanthus yet known have been found 
in the Lower Carboniferous rocks in Europe, Canada, and the United States: 
Sir J. W. Dawson? has described two species of Gyracanthus (G. duplicatus and 
G. magnificus), and refers them to the Coal Measures; but Rev. D. Honeyman 
informs me that G. magnificus was obtained from the Lower Carboniferous 
limestone of Cape Breton. As to the other species, G. duplicatus, it is 
doubtful whether this should be included in the genus Gyracanthus. 
At Berea, the Berea shale, the Berea grit, and the calcareous bands of 
the Bedford shale have all furnished the remains of fishes in considerable 
numbers, viz: In the Berea shale occur the teeth of Cladedus Pattersoni, and 
the striated rhomboidal scales of Palwoniscus (Gonatodus) Brainerdi, and Dr. 
William Clark has here found in the dove-colored clay-shale just above the 
sandstone, several specimens of Physonemus (Stethacanthus) tumidus, to which 
the rays of the pectoral fins are still attached. On the surface of the sand- 
stone he has obtained a large number of these spines, but here denuded of 
all appendages. From the want of symmetry which they exhibit I had 
been led to consider them as pectoral spines. The specimens in which the 
1 Recently another species has been found by Mr. Sherwood in the Catskill rocks of Tioga County, 
Pa. It is described in another part of this memoir. 
2 Acadian Geology, p. 210. 
