470 
PALAEONTOLOGY OF NEW YORK. 
Goniatites Oweni. 
PLATES LXXIII, FIGS. 3-8 ; LXXIV, FIG- 9. 
Goniatites Oiveni, Hall. Thirteenth Rep. N. Y. State Cab. Nat. Hist., pi. 100, figs. 11, 12. 1860. 
“ “ “ Illustrations of Devonian Fossils : Cephalopoda, pi. 73, figs. 3-8. 1876. 
Shell discoid, depressed suborbicidar, with the lateral faces somewhat flattened, 
and the periphery regularly rounded; the greatest lateral diameter equal to 
about twice and a half the thickness of the disc. 
Volutions ventricose, about six to eight or nine, the lateral and ver¬ 
tical, or dorso-ventral, diameters being nearly equal. All the turns are 
exposed in the umbilicus to about one-fourth or less of their width, the 
remaining three-fourths or more being embraced in each succeeding volu¬ 
tion. Umbilicus deep and of moderate width, subject to considerable 
variation; the margins descend by a series of vertical steps, the inner face 
of the volutions being flat and essentially rectangular to the lateral face. 
Transverse section semi-elliptical, the height equal to the diameter at the 
base, which is deeply impressed by the preceding volution, leaving the por¬ 
tion beyond its periphery nearly equal to, or a little more than the embrac¬ 
ing portion of the volution. The rate of enlargement of the volutions, in a 
well-preserved specimen of medium size, is from thirteen mm., the diameter 
of the inner of two volutions, to twenty-one mm., the diameter of the 
outer one, and in a larger individual the proportions are about as twenty- 
one to twenty-eight mm. In a smaller specimen, having its largest diameter 
of twenty mm., the rate of increase is from six to nine mm. in a single 
volution. 
Chamber of habitation not satisfactorily determined. In many specimens 
it appears to occupy more than an entire volution, there being no external 
indication of septa, as in figures 7 and 8 of plate 73; while in other forms, 
of similar dimensions, there are evidences of septa in the exterior volu¬ 
tion. A specimen, having a lateral diameter of ninety mm., and cut in 
horizontal section, shows a full volution and a half, free from air-chambers. 
In one specimen, where the basal portion of the outer chamber is clearly 
