460 
PA L2EON TO LOGY OF NEW YORK. 
Goniatites sinuosus. 
PLATES LXX, FIGS. 13-15; LXX1I, FIG. 11; LXX1V, FIG. 11. 
Goniatites sinuosus, Hall. Geolog-. Surv. N. Y. : Rep. Fourth Dist., p. 243, fig-. 6. 1843. 
“ “ “ Illustrations of Devonian Fossils: Cephalopoda, pi. 72, fig-. 11. 1876. 
“ ( Clymenia ?) Nundaia, Hall. Descriptions of New Species Goniatidse, p. 3. May, 1874. 
“ “ “ “ Twenty-seventh Rep. N. Y. State Mas. Nat. Hist., p. 134. 1875. 
“ “ “ “ Illusti-ations Devon. Fossils’: Cephalopoda, pi. 70, figs 13-15. 1876. 
Shell broadly discoid, with the sides gently curving, or sometimes nearly flat; 
the thickness of the disc is thirty mm. or more in old specimens where the 
lateral diameter is about 100 mm. 
Volutions about three or four, the inner ones gradually enlarging, while 
the outer ones expand much more rapidly and become ventricose in the 
chamber of habitation. The outer volutions embrace the inner ones to an 
extent of one-quarter of their diameter. Umbilicus wide, exposing all the 
inner volutions, its margins nearly vertical, the exterior angle rounded. 
Transverse section semi-elliptical, having a height of once and a half the 
breadth at the base, in the outer volution; the sides curve gently toward the. 
periphery, which is abruptly and regularly convex, having a width about half 
as great as the base, which is two-thirds as wide as the lateral face, and slightly 
indented by the preceding volution; the baso-lateral angles slightly auricu- 
late. The rate of increase, in two outer volutions of a nearly-entire large 
specimen, including more than half a volution of the chamber of habitation, 
is from four to twelve and forty-two mm. The specimen figure 15, plate 70, 
shows an increase in the outer volution from less than fourteen to forty- 
five mm. 
Chamber of habitation large, occupying more than half a volution in entire 
specimens, and having a capacity much greater than all the chambered portion 
of the shell. Aperture semi-elliptical, with the apex somewhat truncate and 
the sides gently expanded. The base is slightly indented by the preceding 
volution, and the baso-lateral angles are auriculate. Air-chambers numerous, 
somewhat irregular, and gradually increasing in depth toward the chamber 
of habitation, except the last one or two, which are shallower than the pre- 
