244 FREDERICK W. SARDESON 



which although circular, appears not to be so because the margin is 

 bent under. In the fossils, the stem is wanting, but from the scar it is 

 seen to have been slender. The upper surface is smooth when well 

 preserved. Suture Hnes show indistinctly that there are quadrangular 

 plates, generally in rows. Fig. 9, arranged radially. Five rows of 

 plates radiate from the center and between these other rows gradu- 

 ally intercalate. The interior is separated into canal-like spaces by 

 partitions which appear to be inward thickenings of the plates, 

 traversing the same along the rows radially. This structure has 

 been seen by means of macerated and weathered specimens only, 

 as is shown in Fig. 10, and the extension downward of the partitions 

 is not exactly determined; but these probably touch the ground 

 layer or fixing plate. 



This type of Crinoidal root is remarkable for its large radius, 

 small height, and relatively small stem-scar. A number of speci- 

 mens were found at a particular part of a quarry where plates of 

 Strophocrinus were abundant, and they are all believed to be struc- 

 tures of one species, i. e., Podolithus strophocrinus = Stropho- 

 crinus dicyclicus. These bases and the plates of Strophocrinus are 

 otherwise rare. Their occurrence is in association with intra-forma- 

 tional conglomerate at the top of zone No. 4 (Stictopora bed) and in 

 zone No. 5 (Fucoid bed) of the Galena-Trenton stage, at St. Paul, 

 Minn. In view of their large size and close association with crown 

 plates, it appears to be most probable that the bases were permanent 

 anchors. 



Podolithus schizocrinus n. sp. 



(Figs. 11-17) 



This species includes stem-bases which are from 3"^™ to 2^^™ 

 in diameter, about one-fourth as high as wide, and in general outline 

 conical but with thick and irregularly lobed margin (Fig. 11). The 

 apex of one small specimen shows a flat circular stem-scar, with a 

 star-shaped lumen, while others seem to have been either excessively 

 macerated or reabsorbed in this part. Generally there is a circle of 

 small pores or canal ends seen just within the rim of the central open- 

 ing. No other openings through the wall appear anywhere. The 

 top surface is dense and smooth with indistinct sutures. Trans- 

 verse thin-section reveals, under the petrographk microscope, that 



