SUBOAKBONIFEUOUS PERIOD. 81 



lacral areas ; interradial plates long and naiTOw, apparently reacliing tlie 

 summit ; a comparatively shallow vertical fuiTow extending along the mid- 

 dle of each ; pseud-ambulacral areas prominent, narrow, reaching down to, 

 or below the plane of, the basal plates. 



Oiir only example is silicified and partly imbedded in siliceous lime- 

 stone, whereby the finer details of structure and ornamentation, including 

 the structure of the parts at the anal side of the summit, are obscured ; but 

 the more conspicuous features are svifficient to indicate its specific sejiara- 

 tion from any similar form known to me. 



Pleight, nine millimeters ; transverse diameter, seven millimeters. 



In general aspect, this little Granatocrimis is much like G. melo (^Pen- 

 tremtes melo Owen and Shumard) from the Subcarboniferous strata at Bur- 

 lington,* Iowa ; but it differs from that species in its less robust form, and in 

 not possessing the distinct longitudinal lobes that suggested to those authors 

 its specific name. 



In that species also, the pseud-ambulacral areas are more or less 

 depressed . below the general siirface of the inten-adial plates, while in ours 

 those parts are the most prominent portions in the outline of a transverse 

 section of the body. If the generic identification of this fossil as distinct 

 from Nticleocrimts is coiTect, as it is believed to be, there seems to be no 

 reason for questioning the Subcarboniferous age of the strata containing it, 

 since the genus as thus restricted is understood to be confined to strata of 

 that period alone. The Subcarboniferous age of the strata is also indicated 

 by other types of that period associated with this species. 



Position and locality. — Strata of the Subcarboniferous period ; Ewell's 

 Spring (upper horizon), Arizona. 



OiiDEE CHINOIDEA. 

 Family PLATYCRINID^. 



Genus PLATYCEINUS Miller, 1821. 



Platycrinus (?). 



Plate V, fig. 2. 



Upon the weathered surface of a piece of limestone in the collections, 

 there are tlu-ee or four more or less imp)erfect Crinoids. They are partly 

 C F 



