7,1 







PLATE LVIII. 



. 



PAGE. 



Fig. 1. LYROPOBA BANOSCULUM Ulr 881 



1. The obverse side of a large specimen showing the basal portion of the 



support and a small portion of the net -work. Natural size. The sec- 

 tional view shows the extent to which the margin of the net-work is 

 covered. 



1 a. The reverse side of another fragment of the support showing the usual 

 prominence of the basal part, natural size. 



1 1>. Obverse face of a branch showing the rather irregular arrangement of 

 the zooecia and tubercles, x!8. 



1 c. Reverse face of a frond, x9, showing the subcircular fenestrules, and 



the flne vermicular markings of the surface. 



Fig. 2. LYBOPOKA SUBQU ADR ANS Hall 582 



2. A specimen showing the attenuated base, natural size. This example is 



unusually strong. 

 Chester, Illinois. 

 E. O. Ulrich's collection. 



2 a. The obverse side of a younger example, preserving a large portion of 



the fenestrated expansion. Natural size. 



Chester, Illinois. 



Illinois State Museum. 

 2 6. Another example, similar to flg. 2, but not plicated. Natural size. 



Chester group, Sloan's Valley, Ky. 



E. O. Ulrich's collection. 

 2 o. Portion of flg. 2 a, showing the relative size and cliara-ter of the 



branches and fenestrules, x9. 

 2 d. Portion of the obverse face, x9. 



2 e. One branch of flg. 2 d, x!8, to show the arrangement of the zooBCia and 



row of nodes, and the granulose surface. 



Fig. 3. LYBOPOKA QTJINCUNCIALIS Hall. (See also PI. LT) 583 



3. The obverse side of the support and a small portion of the fenestrated 



expansion. Natural size. 

 Chester, Illinois. 

 Illinois State Museum. 



3 a and 3 b. Natural size. Reverse and profile views of another specimen 



from the same locality and collection. 

 3 c (e on plate). Poriferous side of net-work, x9. 

 3 d. Reverse face of a fragment, x9. 



