NAUTILTD^. 
03 
“ From the strength and regularity of the transverse folds of the 
test, the internal mould is marked by anmilations, which are more 
prominent on the ventrnm [convex side]. It also shows lamellose 
lines of growth, and the furrows and strim of the creniilations. 
“ The largest individual obseiwed has a diameter across the disk 
of 190 millim., with a diameter to the tube of 42 millim. at the 
aperture. 
“This species is distinguished from Gyroceras Nereus [Hall, Pal. 
Xew York, 1S79, vol. v. pt. ii. p. 373] by the greater number of 
volutions and the character of the surface ornamentation. In 
G. citum [Hall, loc. cit. p. 372] and G. Matlieri [Hall, loc. cit. p. 377] 
the transverse section is different, and the transverse plications are 
more elevated and distant. The individuals of this species are 
comparatively common. . . .” {Ifalh) 
Hoinzon. Upper Helderberg. 
Locality. Scoharie, or the Helderberg Mountains ^ Xew York State. 
Represented in the Collection by a single example. 
CARBOXIFEROUS SPECIES. 
Gyroceras Luidii, ^lartin, sp. 
1809. Conch. N. Ammonites {Luidii), anfractihus e.vtvinsecis teretihus 
&c,, Martin, Petriticata Derbiensia, pi. xxxv. tf. 1, 2, and App. 
p. 16. 
1849. Nautihis Luidii, d’Orbignv, Prodr. de Paleont. Stratigr. vol. i. 
p. 111. 
18bo. Nautilus Luidi, M‘Coy, British Pal. Foss, fa.sc. iii. p. 559. 
Sp. Char. “ Discoid, of two and a half gradually increasing 
whorls, not embracing [with a moderately large central vacuity] ; 
mouth [section] transversely oval ; periphery very broad, convex, 
sides narrow, rounded, sloping rapidly with slight convexity, to 
form the wide umbilicus. Entire surface marked with about thirty- 
six subequal, narrow, thread-like keels, slightly smaller on the sides 
of the umbilicus, separated by wider, slightly concave, spaces ; 
about five ridges in three lines on middle of body- whorl, at an inch 
and a half in diameter, closer at smaller size, and fewer in the same 
space when larger ; all the ridges set with small spinulose tubercles. 
’ Buffalo (Nesv York State) is the locality upon the label affixed to the 
specimen ; but thi.s i.s most probably a mistake, as the specie.s has never been 
recorded from that place. 
