SPIRIFERID A. 83 
‘Bulletin de la Société Géologique de France,’ second series, vol. v, p. 334, pl. iu, 
fig. 48, 1848; but I would not again describe it as a Crania, as it seems to differ in 
several important particulars from all the species of that genus with which we are 
acquainted. In all probability it is not a Brachiopod at all. I have, however, carefully 
figured the original example now in the Museum of the Geological Survey of London 
(Pl. VIII, fig. 25), with the hope that by so doing the true nature of this obscure fossil may 
be hereafter determined. Prof. M‘Coy has referred it to his own more than doubtful 
genus Spondylolobus, to which it bears no affinity. 
The so-termed C. Sedgwickii is longitudinally oval and almost flat, with two rounded 
concentric ridges in the proximity of the margin, while small granulations are observable 
here and there over its surface. The inner surface of the fossil is slightly concave about 
the middle, with two raised rounded ridges corresponding to those on the external surface. 
At a little distance inwards, or from what we might describe as the posterior margin, rise 
two irregular conical projections, which are almost contiguous at their base. It measures 
six lines in length by five and a half in width, and was found by Mr. Lewis in the 
Wenlock limestone or shale of the Rushall Canal, near Walsall. 
Famity —lEREBRATULID&. 
No species referable to this important family has with certainty been hitherto dis- 
covered in our British Silurian rocks. One small shell, it is true, has been described in 
the ‘Silurian System’ under the designation of Zerebratula laviuscula, and requoted at 
p- 545 of ‘Siluria’ as a Zerebratula with a point of interrogation ; but, as will be seen in 
the sequel, I believe I have satisfactorily determined, after a careful examination of the 
original specimen preserved in the Museum of the Geological Society, that the fossil in 
question cannot be classed amongst the Zeredratule, as the shell-structure of the so-termed 
T. /eviuscula is fibrous, and not punctured ; and it, moreover, agrees in shape and character 
of beak with Athyris or Meristella nitida, of which it is evidently a young shell. 
Faminy—SPIRIFERID. 
The characters of this extensive family having been already described at some length 
in our General Introduction, and often subsequently adverted to in the Jurassic, Permian, 
Carboniferous, and Devonian Monographs, it will not be necessary to again enlarge upon 
the subject. In our Silurian rocks. Spirifers were specifically very few in number, and 
almost entirely confined to the Upper Silurian period. 
