228 Twenty-third Report on the State Cabinet. 



, Genus — CAUNOPORA Phill. 



Cauxopora planulata n. sp. 



Plate 9, fig. 2. 



Specimens forming flat discoid bodies of greater or less extent and 

 v^arving in thickness, apparently originating at a subcentral point of 

 attachment. Surface of disc irregfilarlj flattened. Centers of cells 

 distinctly marked, scarcely or slightly elevated, and characterized by 

 numerous radiating grooves or channels, which traverse the body in 

 all directions, terminating in the central pore or tube. In a vertical 

 section the hoi'izontal plates are very thin, curving upwards as they 

 approach the central pore, and so closely arranged as to be undistin- 

 guishable except under a strong magnifler ; the vertical columns are 

 much thicker than the intervening spaces, and number about nine in 

 the space of a tenth of an inch. 



This species diflfers from S. {GcBnostroma) incrustans (which in 

 vertical section it closely resembles) by the absence of conical pustules 

 on the surface, or in having them broader and but slightly elevated. 



Formation and locality. In marly beds of the age of the Chemung 

 group ; at Hackberry, eight miles above Rockford, Iowa. 



There may be some doubt regarding the propriety of separating the 

 species here referred to Cauxopora and C^nostkoma, from the true 

 Stromatopora. "When carefully examined under a magnifler they 

 prove to be made up of a series of vertical columns, connected by lat- 

 eral filaments, which radiate more or less regularly at given intervals, 

 and unite the several columns to each other just as in the typical 

 Stromatopora ; and it is these latter processes which, in a vertical 

 section, give the appearance of horizontal plates. The conical pustules 

 of C..EN0STR0MA are only a further development of the rounded emi- 

 nences on the surface of most of the true Stromatopora, which, in tlie 

 natural surface, are covered by a net-work of vermicular cavities larger 

 than the interspace, and often present the same appearance as the mad- 

 reporiform tubercle on the star-flshes. These vermicular passages, of 

 course, represent the ramifying channels on the sui'face and through 

 the substance of C^xostroma and Cauxopora. The latter genus (if 

 we take the typical species of Prof Phillips as an example ) differs from 

 C^NOSTROMA only in the absence or degree of development of the sur- 

 face tubercles ; and. if a specimen of a true species of C.enostkoma be 

 ground down parallel Avith the horizontal layers, it will present the 

 same characters as shown in Prof. Phillips' figure 29 d, plate x. Pal. 

 Foss. 



Genus— FISTULIPORA McCoy. 



FiSTULIPORA OCCIDEXS 11. SJ>. 

 Plate 10, flgs. 9. 10. 



Coral growing in strong, anastomosing branches, or branching 

 masses of from half an inch to two and a half inches in extent, solid, 



