ORinOCERATII)^. 
29 
The Collection contains the specimens described by Salter : — 
Long and very slowly tapering. The septa . . . frequently 
more than two lines apart, and very convex. The siphon is 
frequently out of the middle, and is small where it joins the septum, 
but is swelled into a bead-like shape between them.” 
Horizon. Silurian (Division unknown). 
Locality. Griffith’s Island, Arctic America. 
Orthoceras Belgicum, Malaise. 
1873. Orthoceras Belgiciim, Malaise, Terrain Silurien du centre de la 
Belgique, p. 88, pi. iii. ff. 1, 2. 
Sp. Char. Shell straight. Section elliptical. Bate of tapering 
very slow. Septa unknown. Siphuncle a little eccentric. Surface 
ornamentation consisting only of lines of growth. 
Remarlcs. M. Malaise observes that he possesses numerous casts 
of this form, which are crushed and flattened, and without any 
trace of the test, the septa, or the siphuncle. The largest attain a 
length of about one foot. All these fragments, he adds, are in a 
had state of preservation, and it is impossible to correlate them 
with any other species with any degree of certainty. He there- 
fore bestows a specific name upon them, because of their number, 
and of the similarity of the characters uniting them. 
Horizon. Silurian (exact Division unknown). 
Locality. Grand-Manil, Belgium. 
Represented by a single specimen. 
Orthoceras ascendens^ Blake. 
1882. Orthoceras ascendens, Blake, Brit. Foss. Ceph. p. 132, pi. xii. f. 7. 
Sp. Char. Section circular. Rate of increase 1 in 15. Septa 
unknown. Siphuncle apparently central. Surface ornaments con- 
sisting of “ sharp, upward imbrications which cross the shell 
directly, without any undulation ; they are distant about ^ of a 
line, or the shell diameter.” 
Horizon. Lower Ludlow ? 
Locality. England ? 
Represented by a single example. 
Orthoceras STibundulatum Portlock. 
1843. Orthoceras suhundulatum, Portlock, Rep. on the Geol. of 
Londonderry, p. 373, pi. xxviii. f. 2. 
1843. Orthocei'as incertum, Portlock, loc. cit. p. 347, pi. xxviii. f. 7. 
1845. Creseis SedgwicMi, Forbes, Quart. Journ. Geol. Soc. vol. i. 
p. 146, f. 2. 
