PLATE XXIV. 



PACE. 



Tig. 1. Syringostkoma columnaris 253 



1. Frafftnent. Natural size. 



la, Tertical section of a tiragment. Grreatly enlarged. 



Fig. 2. Syringostkoma densa 251 



2. Portion of the eurfaco of a fragment. Natural size. 

 2a. Small portion of th.e surface. Enlarged. 



2&. Yertioal section of a fragment. Enlarged. 



Fig. 3. Stromatopoea nodulata , 249 



3. Fragment of amass. Natural size. 



3a. Suiface of one of the layers. Enlarged. 

 3&. Vertical section of a fragment. Enlarged. 



Fig 4. Stromatopoea ponderosa ■. 246 



4. Portion ^jf the surface of a large mass, showing oscula. Natural size. For the sake of 



simplicity, it has not been attempted to represent on this scale the tubercles "which cover 



the entire surface. 

 4a. Portion of the surface of the same, showing the tubercles with their pejorated summits. 



Enlarged. , 



46. Yei-ticalsection of a fragment. Enlarged. 



Fig. 5. Stromatopora sub-striatella 248 



5. Portion of the surface, showing oscula and pores. Enlarged. 

 5a. Vertical section of the same. Enlarged. 



Fig. 6. Dictyostroma undulata 254 



6. Vertical section of a fragment. Natural size. 



6a. Upper surface of a fragment, showing the oscula. Natural size. 

 6&. Upper surface of one ot the internal layers of the mass. Enlarged. 



6c. Vertical section of three layers, showing the perpendicular processes and the ends of the 

 horizontal canals which perforate the layers. Enlarged, 



