138 
GEOLOGY OF THE FOURTH DISTRICT. 
1. Cornulites, n. s. — This species differs from the one in the Niagara group, in being 
much smaller, quite straight, and the upper edges of the rings thinner. The upper edges of 
the rings are not horizontal, but depressed on one side uniformly, producing a sort of seam or 
suture. 
Locality —Near Newark, Wayne county. 
2. Orthoceras Iceve, n. s. — Smooth ; annulations numerous ; very gradually tapering; 
siphuncle central. 
This is the only known Orthoceras of the group, and differs from any in this part of the 
system, in its smooth shell, gradually tapering form, and numerous septse. 
Locality —Newark, Wayne county. 
3. Loxonema Boydii, n. s. — Very gradually tapering; last whorl somewhat ventricose, 
slightly umbilicated; mouth imperfect. The marks of the arched or undulating striae, so 
characteristic of the genus, are impressed upon the cast in a few places, and a little of the 
shell is preserved. The summit of the spire is concealed in the matrix, and from its fragile 
nature, it is impossible to remove it. 
This shell is named in honor to the memory of Dr. G. W. Boyd, who was zealously en¬ 
gaged in the New-York Survey during the first two years after its commencement; and after¬ 
wards, until his death, in the Geological Survey of Virginia. 
Locality —Near Newark, Wayne county. 
4. Euomphalus sulcatus, n. s. — Shell rapidly tapering ; whorls about four, last one much 
expanded ; surface marked by spiral furrows and elevated lines of equal width, which con¬ 
tinue into the umbilicus ; aperture circular ; umbilicus large. 
The figures are from two different shells, the lower one representing the base being much 
the larger. The lines and furrows of equal size readily distinguish this shell from any other 
in this part of the system. It resembles the E. sculptus, ( Silurian Researches, p. 626, pi. 
12, f. 17,) in many respects, but is a smaller shell, and has four whorls. 
Locality —Newark, Wayne county—abundant. 
5. Delthyris -? — This species is about the size of T). decemplicata of the Niagara 
group, and since only casts have been seen it is left for further investigation. 
6. Atrypa -? — This species is apparently identical with a form abundant in the Nia¬ 
gara shale, but which has not yet been identified or named. It is interesting as showing one 
form of that group which continued beyond the middle period of the salt group. 
Locality —Newark, Wayne county. 
7. Avicula triquetra, n. s. — Shell obliquely subovate or cuneate ; marked with concentric 
stride ; posterior wing large, abruptly acute ; anterior wing very small. 
Locality —Near Newark, Wayne county. The same apparently, appears in Genesee county 
in the slialy limestone above the plaster beds. 
