PLATE XXIII. 



Heliophtllum Halli. 



Strombodea helianthoirhs (Goldf.) Hall. Geology of N. Y. Surv. Fourth Geolog. Dist. p. 209, f. 3. 1843. 

 Heliophyllum Halli Edw. aud Haime. British Foss. Corals, introd. p. Ixix. 1850. 



Polyp. Foss. des Terr. Palteozoiques, p. 408, pi. 7. fig. 6. 1851. 



Figs. 1-3. Views of three specimens diflering in form of coralUim and depth and size of cup. 

 Fig. 4. Longitudinal section, showing the depth of cup and interior structure. 

 Fig. 5. Transverse section of a similar form. 



Fig. 12. An enlargement of a section of the specimen Fig. 5, showing the transverse ridges of the 

 lamellie and the interradial vesicular plates. 



Hamilton group, in numerous localities in Western New York. 



Heliophtllum Halli var. reflexum. 



Fio-. 6. Lateral view of a young specimen, showing the reflexed cell-margins and distant lamella?, 



with a comparatively small and shallow depression. 

 Fig. 7. A similar view of a larger individual. 



Figs. 8-10. Three views of a large specimen, having the top somewhat more flattened. 

 Fig. 11. An enlargement from the surface of the same, showing the projecting transverse ridges 



and the interradial vesicular plates. 



Hamilton group, Livingston county. New York. 



