122 W. U. Iludlesion — On the YorhsMre Oolites. 



of var. B. be found, either in Yorksbive or elsewbere, tbe case would 

 be altered. Phillips's type may be examined in the York Museum. 

 Descriptions. — The usual Forbi. Specimen from the Scarborough 

 Limestone (zone 3), Cloughton (?), Bean Collection, British Museum. 

 Figs, 1, 1«, 16. 



Height 8 millimetres. 



Width 7-5 ,, 



Spiral ano-le 60°. 



Eatio of body-whorl to entire shell 36 : 100. 



Shell small, conical, imperforate. The spire increases under a 

 very regular angle, and is nearly equilateral. Whorls perfectly flat, 

 suture extremely close (so close that it is not eas}' to count the number 

 of whorls). The ornaments consist of five (?) equal spiral bands 

 which are rather close together and evenly tuberculated, the tubercles 

 or granules being nearly circular, or at least only slightly drawn out 

 spirally ; the body-whorl possesses four of these tuberculated spirals, 

 together witli a thicker belt constituting the basal periphery. 



Base nearly flat, outer area spirally striated ; columellar area 

 nearly smooth, or only marked with faint radial lines. Aperture 

 rhomboidal and depressed, with a very short columella, which 

 possesses indications which might be interpreted as representing a 

 tooth. 



Vaeiety B. — Specimen from the Cornbrash (zone 4), Scarborough. 

 Leckenby Collection. Not figured. 



In size and proportions almost identical with the last ; it corre- 

 sponds also with specimens from the Scarborough Limestone in the 

 perfectly conical outline, and in the closeness and comparatively 

 large tubei'culations of the spirals. The difi'erences are, that the 

 ■uppermost spiral is bi-tuberculate and constitutes a very slight pro- 

 minence or zone : on the other hand, the basal belt of the body- 

 whorl is sharper and less broad than in specimens from the lower 

 horizon. 



Relations and Distribution. — This species must be regarded as the 

 representative of the small, conical, granulated or tuberculated 

 Trochids, which occur throughout the Lower Oolites more or less 

 sparingly. Turning to the IPaleontologie Frangaise, we find such 

 species as T. Brutns (T. J. p. 283, pi. 315, figs. 13-16), T. Luciensis 

 (p. 288, ph 317, figs. 5-8), and T. Zenohius (p. 289, pL 317, figs. 

 9-12), all more or less near to T. monilitevtus. T. Zenohius is very 

 near indeed, but is represented as having four spirals. Trochns 

 eutrochus, Laube (Gaster. von Balin, p. 10, pi, 2, fig. 5), also belongs 

 to this group : it is stated by that author to occur in the Great Oolite 

 of Bayeux, and rarely in the Brown Jura of Balin. It would be 

 unsafe to say how nearly these forms are identical with Phillips's 

 species, 



T. 7nonilitecttis, or a very similar form, occurs in the Lincolnshire 

 Limestone, and also in some of the shell beds of the Inferior Oolite 

 of the Cotteswolds. But there are certain differences of ornamenta- 

 tion, and specimens from the same bed exhibit, some four, some five 

 spirals : hence it is not easy to say how far such indications are of 



