

PLATE 1,1. 



PAGE 



Fig. 1. FENESTELLA EXIGUA Ulr 545 



1. Obverse face of the best specimen seen, showing the narrow and flightly 



flexuous branches, x9. 



1 (i. Reverse face of same, x9. The tubercles are not as strong as usual. 



Warsaw beds, Monroe Co., 111. 

 Illinois State Museum. 



Fig. 2. FENESTELLA TENAX Ulr 546 



2. Obverse face, x9, showing the usual appearance of the Warsaw beds form. 



2 a. Portion of same. x!8. 



2 6. Reverse aspect of another fragment, x9. 



Monroe Co., 111. 



Illinois State Museum. 

 2 c. Several branches of a specimen of the Chester group form,x!8. This 



agrees with the Warsaw beds specimen. 

 2 <J. A branch and two rows of fenestrules, x!8, showing their usual form 



and relative size. 



2 e. The reverse side of a branch of a variety with larger fenestrules and 



only 24 or 25 cells in 5 mm., x!8. 

 Chester group, Sloan's Valley, Ky. 

 E. O. TJlrich's collection. 



Fig. 3. FENESTELLA ELEVATIPOBA Ulr 549 



3. Obverse side of a fragment, x!8. As seen lying on the surface of slabs 



the nearly flat branches appear almost to be in contact. 



3 o. Reverse side of another fragment showing the strong rounded stria- 



tions, x!8. 



Chester group, Kaskaskia, 111. 



Illinois State Museum. 



Fig. 4. FENESTELLA FLEXUOSA Ulr 548 



4. Obverse face of a fragment, x9, showing strongly flexuous branches. The 



tubercles on the keel are not shown strong enough. 



4 a. Reverse side of another specimen, x9, showing the usual appearance of 



this side. 



4 6. Several branches of a very perfect fragment, with the branches some- 

 what more rigid than in fig. 4, xi. 



4 c. End view of several branches showing their form and the elevations of 

 the tubercles, x9. 



Chester group, Sloan's Valley, Ky. 

 E. O. Ulrich's collection. 



