(PA) 
DIVISION IV. ORTHOCERACEZ. 
4. Brremnites. Boet. de 
Boot. 
A thin double case, 
composed of two cones 
united at their bases ; 
the interior cone much 
shorter than the other, 
divided within by paral- 
jel septa, concave towards 
the base ; only one cham- 
ber (conical) apparent, the 
older ones being succes- 
sively effaced by the piling 
up and contiguity of the 
septa. Pl. 4, fig. 9, 22, etc. 
GENERA. 
A siphon extending 
from the summit of the 
exterior to the same part 
of the interior cone, 
whence it continues ei- 
ther along the edge or 
through the centre of the 
septa. 
Very abundant, es- 
ecially in strata of 
Chalk and Compact 
Limestone. 
a. Elongated in cylinders, sharpened at the end only. 
6. Narrowed towards the base, like a distaff or lance. 
2. OrtHOcERATITES. Brey- 
nius. 
Straight or slightly bent; 
chambered; margins of 
the septa even, or with 4 
or 2 small undulations. 
A 1, fig. 25. Pl. 2, fig. 
3. ConuranitEs. Miller. 
Concave, hollow, mouth 
half closed by an inflexion 
ofthe lip. Pl. 3, fig. 19,24. 
4. AmpLExitTEs. Sowerby. 
Nearly cylindrical; di- 
vided into chambers by 
numerous transverse sep- 
ta embracing each other 
with their reflected mar- 
gins. Pl. 2, fig. 10. 
5. Noposaria. Lam. 
Straight, chambered, 
slender, with a contrac- 
tion at each septum. 
A siphon central or 
lateral. 
Septa imperforate. 
Said to characterise 
the Transition Rocks of 
Werner. 
In Transition Lime- 
Stone, in Ironstone, in 
Schale, with marine 
shells. 
In the Bimestane of 
the Black Rock at Lime- 
rick. 
Akin to the Raphanis- ~ 
ter (PI. 2, fig.15), Echid- 
nus (PI. 2, fig. 14), and 
Telebois (Pl. 3, fig. 22) 
of Montfort ? 
B 
