248 W. H. Hudleston — On the Yorkshire Oolites. 



Description (Fig. 9). — Specimen from the Millepore Bed (zone 2), 

 Clougliton Wyke (Sycarham). Leckenby Collection. 



Length 13-5 mm. 



"Width 3-5 „ 



Spiral angle 18~'. 



Shell conical, elongate. Spire composed of about ten whorls, 

 which are nearly flat, short, and not deeply divided. Strong longi- 

 tudinal (i.e. transverse) ribs, very slightly curved, and inclined, but 

 without visible decussation. Base spirally ribbed. 



The aperture is so far involved in matrix as to render it uncertain 

 whether there be a slight anterior notch or not. This is the case 

 unfortunately with all the specimens from the Millepore and from 

 the Dogger. 



Fig. 10. — Same horizon and locality. Bean Collection, British 

 Museum. 



Fig. 11. — Specimen from the Dogger, Peak (Blue Wyke). Leck- 

 enby Collection. This has about the same angle as the two pre- 

 ceding specimens, and similar ornamentation. Like all the rest of 

 the group, the base is spirally ribbed, but otherwise there is no 

 decussation. 



It is not easy to say whether such a specimen represents the early 

 stage of Chem. vetusta-mojor, next to be described, or whether it 

 should be simply placed under the head of Ch. vetusta. 



Belations and Distribution. — Some idea of the relations of this, the 

 type form, may be gathered from the previous remarks. It is most 

 abundant in the Millepore bed at Sycarham, where the specimens 

 rarely exceed in size those figured. 



Fig. 15 represents a short form from the Millepore bed having 

 similar ornaments. Fig. 16 represents a very elongate form from 

 the Dogger. The latter might almost be worthy of some varietal 

 designation such as attenuata. 



17. — "Chemnitzia" vetusta major, pi. VI. Fig. 12. 



Description. — Specimen from the Dogger (zone 1), Peak (Blue 

 Wyke). Leckenby Collection. 



Length (restored) 43 mm. 



Width 10-5 „ 



Spiral angle 18". 



Shell turrited, elongate. Suture deeply cut, sutural angle but 

 little inclined. Whorls 12 or 13 in number (9 preserved), short; 

 the anterior ones somewhat step-like, and almost devoid of convexity. 

 Strong longitudinal (i.e. transverse) ribs, having a crescentic curve, 

 characterize the spire. No spiral striae are seen on the ribs of the 

 apical whorls. The five anterior whorls have the longitudinal 

 ribbing decussated spirally, producing nodes at the points of inter- 

 section. In the last two whorls the longitudinal ribbing becomes 

 fainter anteriorly, whilst the spiral ribbing on the top of these two 

 whorls becomes more pronounced, presenting somewhat the appear- 

 ance of a nodular varix, which much increases the turrited aspect of 

 the shell. Base strongly ribbed spirally. 



Aperture imperfectly preserved. 



