239 



ACERVULARIA Scliweis-,tf. 



ACERVULARIA DAVIDSONI Milne— Edwa ids and Hnime. 

 [Pal. Fo=B. des Terr. Pal. P. 418. PI. 9, Figs. 4-4 b (18-).] •■ 



Coral composite, astraeiform and massive, composed of unequally sized, 

 usually live or six-sided corallites, having both an outer and an interior, 

 slightly undulated or zigzag wall. The outer wall is thin; the inner wall 

 is rarely well defined; the surface sinks, at first gradually and then 

 abruptly, to form the cup, the diameter of which is about one-fifth of an 

 inch. The bottom of the true calice is flat to slightly elevated. The 

 s('pta> are radially arranged, and are stout and finely denticulate, there 

 being about seven denticulations in the space of one line. They are 

 usually about forty-two in number, and for the most part, extend into 

 the true calice. The tabuhx' are abundant in the central area; the dis- 

 sepiments a1)undant in the periferal zone. The diameter of the larger 

 corallites is about one-half inch. 



This species is most nearly allied to A. Profunda Hall, from which it 

 is distinguished by the larger size of the corallites, the greater constancy 

 in the size of the calices. the less number and less conspicuous denticula- 

 tion of the septa, and in tlie zigzag undulations of the outer walls. 



Range and Distribution. — Devonion formation, on the government trail, 

 four miles east of Canyon Creek, Arizona; on the John Dazen trail, three- 

 fourths mile southeast of the cliff houses, near Oak Creek, and along the 

 rim of the Tonto basin. Arizona; at the falls of the Ohio and at Sandusky, 

 Ohio, etc. 



CERIOCRINUS? 

 Plate, Fig. 3. 



The specimens referred to this genus are a few detached plates and 

 are insufficient to fully identify even the genus. 



Position and Locality.— Upper Rett Wall, north bank of White Rivci' 

 Canyon, twelve miles southwest of Fort Apache, Gila County, Arizona. 



ARCH.EOCIDARIS McCoy. 



ARCH.EOCiDARIS. 



Plate, Fig. 7. 

 The specimens here called ArcJiaocidaris are some fragments. They are 

 too imperfect for identification of tlie species; but, though much worn, 

 are sufficient to identify the genus. 



•■'For a figure of the fossil here described the reader is referred to plate XXX of ihe 

 November number of the American Geologist for 1903. 



