12 
XAniLOIDTlA. 
Honzon. Black Elver Formation ( = LlandeEo Limestones ?) ; Cin- 
cinnati Group ( = Bala ?) 
Localities. GrenvUle, on the Eiver Ottawa ; Montreal ; and “ near 
Quebec”: Canada. Cincinnati and WaynesviEe, Ohio: Xicholas- 
ville, Kentucky. 
Fairly well represented. 
Orthoceras sodale, Barrande. 
1870. Orthocera-s sodale, Barrande, Syst. Sd. de la Boheme, vol. ii. 
Texte iii. 1874 (j angler), p. 4*53, pi. ccccxvii. ff. 9-21. 
? 1882. Orthoceras expansum, Blake, British Foss. Ceph. pt. i. p, 118, 
pi. vi. f. 15. 
Sp. Char. Shell much elongated; very slowly increasing at the 
rate of about 1 in 18. The section is circular when the specimens 
have not been compressed. Body-chamber imperfect in all the 
examples met with. That which is preserved of it measures five 
times the diameter of its base. Septa distant, varying from | the 
sheU-diameter in young individuals to ^ in adults. The siphuncle 
is smaE and central, and probably cyfindrical. Surface-ornamenta- 
tion consisting of fine, sEghtly undulating riblets. 
BeraarTcs. Professor Blake’s species agrees with Barrande’s in aE 
respects except in the rate of increase, which is stated to be rapid 
in 0. expansum. But considering that the outEne of the individual 
figured by Blake is partly concealed by a covering of matrix, the 
latter character may have been inadvertently exaggerated. It is 
worthy of note that the original label attached to one of the specimens 
in the National Collection is “ Orth, centrale ? His.,” this being the 
species which Blake finds his 0. expansurn “ nearly corresponds to.” 
Horizon. Etage D, bande d 5 (=Middle Bala ?). 
Locality. Leiskow, Bohemia. 
FaEly weE represented. 
Orthoceras carinatum ?, Miinster. 
1840. Orthoceratites carinatus, Munster, Beitrage zur Petrefactenkunde, 
Heft iii. p. 100, Taf. xix. ff. 8, a, b, c. 
1868. Orthoceras teres, Barrande, Syst. Sil. de la Boheme, vol. ii. Texte 
iii. 1874, p. 416, pi. ccxcvui. fi: 1-5, pi. ccxcix. fi. 17-24. 
Sp. Char. Apex {Spitz) conical, narrow, somewhat compressed, 
hence elliptical in cross-section : upon the back is a raised keel, 
upon which the transverse wavy acute striae of the outer thick sheE 
run, the intermediate sheE smooth ; a verv smaE central siphuncle, 
the narrow septa transversely undulated.” {Hunster.) 
Bemarl's. The rate of tapering is slow, about 1 in 1.5. I can find 
