DISCOID CRINOIDAL ROOTS AND CAMAROCRINUS 247 



from the rounded angles of the stem. As the specimen is, there 

 appear distinct depressions of the top surface between the radial 

 prominences where not covered by the overturned margin. 



The stem's surface is marked by slightly raised transverse ridges, 

 and a little weathering has brought intermediate rows of small pores 

 to view. The exposed end of the stem shows numerous fine radiating 

 anastomosing furrows, and a few larger ones. These were evidently 

 canals between segments of the unbroken stem and the pores on the 

 outer surface are obviously the ends of the same. The pores are 

 united superficially by suture-like lines which give the stem the appear- 

 ance of consisting of small plates. Meek describes a very similar 

 structure in his specimen (see Fig. 5.). At each angle of the stem 

 is a coarse suture. By observing these described marks, it is seen 

 that the stem on my specimen extends down 5™"^ from the top, and 

 consists of about eight circles of thin undulating plates, which alternate 

 in five vertical rows. 



The surface below the stem shows faint close sutures, indicating 

 that the top of the root proper is made up of numerous polygonal 

 distributed plates. 



Podolithus eucheirocrinus n. sp. 



(Figs. 20-23) 



This species includes bases, the conical form of wliich is concealed 

 more or less by long root-hke lobes of the margin. The largest 

 specimen is grown around a Crinoid stem so that the lobes or radicles 

 extend across one another (Figs. 20, 21). One small specimen has 

 grown obliquely on a curved surface and has the lobes at the sides 

 and lower margin only well extended (Fig. 23). The top or outer 

 surface is dense, and consists of polygonal plates, though the sutures 

 are in part indistinct. About the stem-scar the plates appear sub- 

 hexagonal, alternating in radial rows, while on the lobes or radicles 

 and their branches, the plates are transversely elongated and alter- 

 nate in two rows (Fig. 22). The radicles are flattened on top but con- 

 vexed on the sides. 



The stem-scar is obscured on each specimen, and no stem frag- 

 ment being attached, identification of these roots with any columns 

 is uncertain. They are associated with Crinoid columns like the one 

 upon which a root has grown (Fig. 20), which has five rows of colum- 



