. CHONETES OF THE CORNIFEKOUS LIMESTONE. 
mi 
Dorsal valve unknown. 
Surface marked by regular subequal rounded or subangular striae, which 
are often irregularly bifurcated towards the margin or increased by 
intercalations, and sometimes are nearly simple throughout their 
length below the umbo, those of the cardinal extremities being very 
irregular or nearly obsolete. Hinge-line marked oh each side of the 
centre by four or five strong tubular spines which are directed obliquely 
outwards. 
The sinus ip the ventral valve is not uniform, and though evidently a 
normal character where it occurs, it cannot be relied upon for characte¬ 
rising the species. 
This species resembles the C. hemispherica; but the form of all the specimens 
is nearly semicircular, the cardinal extremities nearly flat, and it is never so gib¬ 
bous on the umbo, while the striae are finer and the cardinal spines more oblique. 
In the surface markings, this species is more nearly like C. coronata , but its 
form in the specimens known is quite distinctive. 
Geological formation and locality. In the Corniferous limestone, near Williams- 
ville; Clarence-hollow; and Stafford, New-York; and in the same limestone at 
the Falls of the Ohio. 
Chonetes lineata. 
PLATE XX. 
Strophomena lineata : Vanuxem, Geol. Report of the 3d District New-York, p. 139. f. 6. (The figure 
6 is placed by mistake at the side of a section of Ichthyodorulite, f. 7.) 
Chonetes glabra Hall in Tenth Report on the State Cabinet, p. 117. 1857. 
Compare Strophomena crebristriata, Conrad, Jour. Acad. Nat. Sciences, Philadelphia, Vol. viii, pa. 254, 
. pi. 14, f. 3. 
Also Chonetes scitula, Tenth Report on the State Cabinet, p. 147. 
Also Strophomena lineata, Conrad, Annu 1 Report, 1839, p. 64. 
Shell subhemispheric, semioval in outline, with the cardinal line 
equalling or greater than the greatest width of the shell below. 
Ventral valve very convex, often ventricose, a little flattened in the 
middle, regularly curving to the front and lower lateral margins, more 
abruptly depressed at the sides, with the cardinal angles somewhat 
flattened and often a little deflected to the ventral side. 
[ Palaeontology IV.] 
16 
