‘28 MOLLUSCA. Goniatites. 
168. A. vakicostatus. —The Variously-Ribbed Ammon¬ 
ite, pi. XX. fig. 8. 
Ammonites varicostatus. Buckland, Geology and Minera¬ 
logy considered, II. p. 62, pi. 42. fig. 7* 
Discoidal, with six two-thirds exposed rounded volutions ; 
the inner ones crossed by numerous, narrow, greatly elevated 
close set ribs, which are bifurcated on the rounded ambit; 
near to the termination of the outer volution the ribs become 
large, broad, distant, and slightly curved, and are destitute 
of the dorsal bifurcation ; aperture oblong-ovate. Greatest 
diameter nine inches. 
Found in the Oxford Clay at Hawnes, four miles south of 
Bedford. 
169- A. hotundus. — The Round Ammonite, pi. XX. 
fig. 10. 
Ammojiites rotundus. Sowerby, Min. Conch. III. p. 169, 
pi. 293, fig* 3. Fleming, Brit. An. p. 243. De la Beche, 
Geo. Manuel, p. 374. 
Discoidal; volutions exposed ; sides crossed by numerous 
thick ribs, which become bifurcate as they pass over the 
back ; aperture orbicular, interrupted only by a small sinus, 
from the insertion of the preceding volution. 
This species is nearly allied to Ammonites biplex , pi. V. 
fig. 10, but distinguished from it, by the ribs being less 
numerous, thicker, shorter, and not so regularly bifurcate in 
passing over the ambit; some are trifurcate ; the sides are 
less compressed. 
Found in the Kimmeridge Clay, at Purbecks, and occurs 
in the Inferior Oolite of Normandy. 
170. A. fimbriatus. —The Fringed Ammonite, pi. XX. 
fig. 12. 
Ammonites fimbriatus. Sowerby, Min. Conch. It. p. 145, 
pi. 164. Fleming, Brit. An. p. 242. De la Beche, Geo. 
Manuel, p. 372. 
Discoidal; with cylindrical volutions, the inner ones 
entirely exposed, crossed by numerous lines of growth, 
which have fimbriated margins; aperture orbicular, pro¬ 
vided with an undulating frill. 
Found at Lyme Regis, Dorsetshire, in the Blue Lias; 
and in the Lias of Yorkshire, and middle and south of 
England. 
Genus V. — GONIATITES. — Vm Buck. 
Shell discoidal, generally very convex or nearly 
globose, most of the species deeply umbilicate ; the inner 
volutions much, or wholly concealed; with internal, 
strengthening, transverse ridges. 
1. G. Looney 1 . — Looney’s Goniatite, pi. XXI. fig. 1, 2, 
and 3. 
Goniatites Looneyi. Phillips, Geology of Yorkshire, II. p. 
236, pi. 20, fig. 33, and 35. 
Depressed, glabrous, sides covered with sigmoidal stria*; 
umbilicus very small ; aperture elliptical; provided with 
numerous septa; the dorsal and lateral sinuses double and 
widely set; but merely waved in immature shells. 
Discovered in Iligh-Green Wood, near Todmorden, Hud¬ 
dersfield, Lancashire. 
2. G. Gilbertsoni —Gilbertson’s Goniatite, pi. XXI* 
fig. 4, 5. 
Goniatites Gilbertsoni. Phillips, Geology of Yorkshire, 
II. p. 236, pi. 20, fig. 27, 28, and 31. 
Depressed ; elliptical, glabrous ; sides covered with greatly 
bent, minute striae; umbilicus small; aperture oblong; septa 
numerous, with round lobes and sinuses ; the dorsal sinus 
double and wide, the lateral sinus simple. 
Locality unknown. Named in honour of Mr Gilbertson, 
of Preston, a zealous and acute naturalist. 
3. G. paucxlobus. —The Few-Lobed Goniatite, pi. XXI. 
fig* 67. 
Goniatites paucilobus. Phillips, Geology of Yorkshire, 
11. p. 236, pi. 20, fig. 36 to 38. 
Depressed; sides with waved striae, and shallow undula¬ 
tions ; umbilicus minute; aperture elliptical; the lobes and 
sinuses of all the septa are round; the first lateral one very 
large. Distinguished from the Goniatites implicates, fig. 58. 
by the form of its lateral sinus. 
4. G. discrepans. —The Discrepant Goniatite, pi. XXI. 
fig. 8 and 15. 
Goniatites Looney i. Phillips, Geology of Yorkshire, II. 
p. 236, pi. 20, fig. 32 and 34. 
Discoidal, smooth, with a minute umbilicus ; striae doubly 
undulating; slightly compressed towards the ambit; aper¬ 
ture oblong ovate; septa numerous, with double, wide dor¬ 
sal and lateral sinuses. 
This species differs from the Goniatites Looneyi , fig. 1, 2, 
and 3, in not being depressed, in the more rounded contour 
of the disk, in the aperture being more ovate, and sharper 
next the back, and in the indentation from the volution being 
more acute. 
Locality unknown. 
5. G. Striolatus. —The Grooved Goniatite, pi. XXI. 
fig. 9, 10. 
Goniatites striolatus. Phillips, Geology of Yorkshire, II. 
p. 234, pi. 19, fig. 14 to 19. 
Nearly globular, sides somewhat flattened, ambit broad ; 
with spiral and transverse, very delicate striae; umbilicus 
very small ; aperture ovate; septa having very wide, acute, 
dorsal sinuses, and the lateral lobes much widened and 
rounded. 
This species differs much in its infant and adult condi¬ 
tions. When very young it is nearly globular, the umbilicus 
much larger, in proportion to the size of the disk, and more 
acute at the edge than in the adult; the constrictions are 
more parallel, and the striae more straight and simple. As 
it advances in ago, the sides become more compressed, the 
constrictions a little undulous, as in fig. 9 ; and when the 
shell is mature the constrictions become obsolete, and the 
angularity of the umbilicus is entirely lost; and the septa 
and striae hardly vary ; as seen in the more elliptical and 
beautiful contour of fig. 10. 
This species may easily be confounded with the G. 
obtusus , fig. 11 and 12, but may be distinguished by its sides, 
being less parallel than those of that shell. 
Found in the Shale, at High-Green Wood, near Hudders¬ 
field ; and in Shale, at Kulkeagh, near Enniskillen, Ireland. 
6. G. obtusus —The Obtuse Goniatite, pi. XXI. fig. 11, 
12. 
Goniatites obtusus. Phillips, Geology of Yorkshire, II. p. 
234, pi. 19, fig. 10 to 13. 
