} 
W. H. Hudleston—The Yorkshire Oolite. 403 
classes the preceding species with this one. I have not seen the 
original description, but quote from De Loriol and Pellat, who point 
out the differences. 
Description.—Fig. 8a. Specimen from the Coralline Oolite of 
Pickering, amongst the Trigonia-beds (my Collection). 
PE OP ivctlaie se iics om So igiguiiendacdnen chee 25 millimétres. 
VEO Bs 6 o4s,s cle, 5 ad tet a SRO M RE a daar fans. ae (Re 
Spiral angles ci. ocd ccteissee sce dade bees es 22°. 
Shell elongated, turrited, sharply pointed. Whorls about fifteen in 
number, increasing under a regular angle, and separated by well- 
marked sutures. They are nearly flat and distinguished by very 
bold ornaments. These latter consist of broad transverse ribs, four 
in number, on all the whorls except the last, and they decussate with 
very stout longitudinal ribs, which on the penultimate whorl are 
about sixteen in number. These ribs have a considerable inclination 
from the axis of the spire, and are sharply separated by the suture 
from those in the adjoining whorl, with which they do not always 
correspond. ‘The intersection of the two systems of ribbing gives 
rise to a set of spiny nodes; the upper one in each whorl is usually 
the most prominent and spiny. The last whorl is slightly less flat 
than the others; it has the same character of ornament, though in a 
less marked degree. The longitudinal ribbing is not continued in 
the base of the whorl, which, however, is ribbed transversely. 
Aperture imperfectly preserved. 
Fig. 8b represents a variety of this species from the same place, 
but in a different state of preservation. Originally this shell seems 
to have been more turrited than Fig. 8a. The points of the spines 
have been ground down. 
Fig. 8c represents a variety where the longitudinal ribs are not 
developed in the under whorls. 
Relations and Distribution.—There is a considerable difference in 
all three of these specimens, but they agree in having only four 
spiral ridges or ribs. Fig. 80 is strongly turrited; Figs. 8a and 8e 
less so. Not known to me in Yorkshire above the base of the 
Coralline Oolite at Pickering. This form occurs in the Lower 
Calcareous Grit. 
EXPLANATION OF PLATE XIII. 
Fic. la. Chemnitzia Heddingtonensis, Sow. Base of Coralline Oolite, Pickering. 
Back view. My Collection. 
1d. 9 a Another specimen to show the aperture. Coral- 
line Oolite of Ness. My Collection. 
Young specimen. Shell with punctate structure. 
le. 
i, is 4 Coralline Oolite of Malton. My Collection, 
etka ‘3 oy Younger specimen. Coralline Oolite of Ample- 
forth Beacon. My Collection. 
Para: 3 Pollux, D’ Orb. Coral Rag of Langton Wold. My Collection. 
Hwee Fe Langtonensis, Bl. & H.; Coral Rag of Langton Wold. 
My Collection. 
$5; 4: ‘3 cf. corallina, D’Orb. Probably from the Coral Rag of Lang- 
ton Wold. Leckenby Collection. 
