EXPLANATION OF PLATE VI. 



Fig. 1. LiTnosTKOTiON Wiiitneyi. (Pago 103.) 



a. Mass of embedded corallite.s, natural size. 



b. Longitudinal section of a corallito, showing vesicles, tabala), and, in part, the columella. 



c. A similar section, made a little to one side of the columella, so that the tabuhe seem to be 



)ilaiu. 

 Fig. 2. CiijETetes mh.leporaceus. (Pago 98.) 



a. Side view of broken siiecimen, showing capilliforni tubes. 

 Fig. 3. Z.Vl'HKENTIS EXCENTKICA. (Page 101.) 



a. Side view, showing a part of (he calyx, the greater part being broken away. 

 Fig. 4. LopiiopnyLLUM pisoliferum var. sauijidens. (Page 101.) 



a. Side view of rather large example. 



if*. Longitudinal section of the same, the cal.yx tilled wilb stony material. 



e. Transverse section of a coiallum, just below the calyx. 



d. Broken example, showing (he manner in which the outer portions separate from the 



col nm el 1.1. 



e. Typical example of L. proViferum from Springfield, 111. 

 Fig. 5. Rhombopora LEPiDODENDROiDES. (Page 99.) 



a. Fragment of a corallum, natural size. 

 6. Part of the same, enlarged. 



c. Small part of the same, still more enlarged. 



d. Portions of silicitied stems, having calcareous cores. 

 Fig. 6. Fcsulina cylindrica. (Page 96.) 



a. Elongate form, natural size. 



h. Subglobosc form, natural size, a little broken at each end. 

 Fig. 7. Archjjocidaeis ornatus. (Page 104.) 



a. Side view of one of the principal spines. 

 Fig. 8. ARCTiyEOCiDARis TUUDiiEn. (Page 104.) 



a. One of the principal spines, rather above average size. 



6. Interambulacral jilate. 



