CEPHALOPODA. 
4G3 
surface striae are coarser. It differs from G. Patersoni in the volutions being 
more exposed in the umbilicus; in the broader and shallower median saddle, 
and the lesser length and angularity of the lobes upon the lateral faces. 
Formations and localities. This species occurs in the Portage shales and sand¬ 
stones, near Mount Morris, Livingston county; near Portland Harbor, Chau¬ 
tauqua county; above the lower falls at Portage, and in a similar geological 
position at Truxton, in Cortland county. It also occurs in the Portage and 
lower part of the Chemung group, near Ithaca, N. Y. 
Goniatites peracutus. 
PLATES LXIX, FIG. 8 ; LXXIV, FIG. 13. 
Goniatites 'peracutus, Hall. Illustrations of Devonian Fossils: Cephalopoda, pi. 69, fig-. 8. 1876. 
The only specimen observed is a fragment, which has been extremely 
macerated, and the surface-characters entirely removed. The form has been 
discoid; and it mav be inferred that the transverse section was semi- 
elliptical. 
The inner volutions are embraced in the outer one; the rate of their 
enlargement cannot be estimated. The umbilical depression is narrow in 
the cast, and the inner volutions were probably not at all exposed in the 
shell. 
The fragment preserves a small portion of the chamber of habitation, and 
a few of the air-chambers. 
The septa, from their origin, curve a little forward, continuing in that 
direction nearly to the middle of the lateral face of the volution, when they 
curve abruptly backward on a line almost parallel with the periphery, 
describing a deep, obliquely semi-elliptical lobe, which, measured from the 
summit of the saddle at the most advanced curve of the septa to the bottom 
of the lobe, has a depth equal to the semi-diameter of the volution. From 
the bottom of this lobe the septum advances abruptly forward, describing a 
very acute saddle, the summit of which is within a few millimetres of the 
periphery, and thence abruptly recurves and passes over the margin of the 
disc. 
