Plate LVIII Continued. 



Fig. 4. LYBOPOBA DIVERGENS Ulr 



4 and 4 a. Two specimens of this species, natural size. 

 Ch< ster, Illinois. 

 Illinois State Museum. 

 4 6. Obverse face, x9, showing two and three ranges of zooecia, and other 



peculiarities of the species. 



4 c. Portion of the reverse side of a large expansion from Chester. 111., 

 which probably belongs to some other species. x9. In its measure- 

 ments it agrees more closely with L. quincuncialis. 



4 d. Eeverse aspect of the frond of a more typical specimen, x9. 



Fig: 5. LYBOPORA OVALIS Ulr. (See also PI. LV) ............. MV.iM&A. JWiVi 



5. View of the only specimen seen. Natural size. 



5 a. Surface of same, x9, showing the characters of the reverse face of the 



frond. 



5 b. Thin section, x!8, showing two ranges of cells, their large size and 

 structure at different levels. 

 Chester group, Litehfleld, Ky. 



PAOE. 



594 



lo 



SK . 



E. O. Ulrich's collection. 



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nd .a .aft oj Tiilhni* .y 



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iv oils 

 -x . 



