8 
NAUTILOIDEA. 
From 0. distans it is distinguished by its closer septa and more 
slender proportions. 
Horizon. Llandeilo Flags and Middle Bala. 
Localities. D’Aran-y-Gesil slate- quarry, near Machynlleth, Me- 
rionethshire (Llandeilo) ; Piedmont Glen, Knockgeirn, Ayrshire 
(Middle Bala). 
Eepresented by very fine specimens, tv^o of them figured by 
Salter, loc. cit. 
Orthoceras Pomeroense ?, Portlock. 
1843. Orthocer'as Pomeroense, Portlock, Eep. on the Geol. of London- 
derry, p. 370, pi. xxvi. f. 4. 
1843. Orthoceras irregular e, Portlock, loc. cit. p. 375. (Not of Miin- 
ster,) 
1843. Orthoceras complanatoseptum, Portl. loc. cit. p. 374, pi. xxviii. B, f . 1 . 
1843. Orthoceras tumidum, Portlock, loc. cit. p. 373, pi. xxviii. ff. 5, G. 
? 1843. Orthoceras regulare, Portlock, loc. cit. p. 377, pi. xxvii. f. 4. 
1882. Orthoceras Pomeroense, Blake, Brit. Foss. Ceph. p. 123, pi. xi. f. 1. 
Sp. Char. Section probably elliptical. The rate of increase 
“ probably between 1 in 14 and 1 in 17, allowing for the fiattening. 
The body-chamber has in one example a length of inches, which 
is about twice the length of the basal diameter, if that were 
unaltered” {Blalce). Siphuncle slightly eccentric. Septa direct, 
distant about J the diameter. Surface with irregular transverse 
lines of growth, some of which are stronger than others. 
BemarTcs. I have referred a crushed fragment to this species as 
interpreted by Professor Blake (loc. cit.). 
Horizon. Lower Llandeilo. 
Locality. Bound Hill, Stiper Stones, Shropshire. 
Eepresented by one imperfect example. 
Orthoceras fractum, Barrande. 
1870. Orthoceras fr actum, Barrande, Syst. Sil. de la Boheme, vol. ii. 
Texte iii. 1874, p. 129, pi. ccccxv. fl'. 16-20, pi. cccclxviii. flP. 6-9. 
1875. Orthoceras fractum, Tromelin & Lebescontes, Notes sur quelques 
fossiles des gres siluriens d’llle-et-Vilaine, p. 4. 
1876. Orthoceras fractum, Tromelin & Lebescontes, Assoc. Fran 9 - pour 
I’avancement des Sciences, 4me Sess.(Nantes), p. 643, Tabl. C. no. 10. 
1877. Orthoceras fractum, Tromelin, Bull, de la Soc. Linn, de Nor- 
mandie, 3me ser. vol. i. p. 27. 
Bp. Char. This species is found only in fragments, indicating a 
straight and elongated shell. The rate of tapering is about 1 in 9. 
