FOSSILS OF THE WAVERLY GROUP. 251 



erable width from the great thickness of the shell. The inner lip, as seen 

 on a specimen preserving this part of the shell, is much thickened and 

 forms a callus, slightly trilobate and strongly modifying the form of the 

 aperture. Aperture semilunate or reniform, about twice as wide as long. 

 A fragment of the exterior surface preserved is covered with oblique rows 

 of closely crowded, rounded granules, or small tubercles, outside of the 

 median band ; the obliquity of the rows being caused by the quincunx 

 arrangement of the tubercles. The form and ornamentation of the revolv- 

 ing median band has not been fully determined, but is apparently broad 

 and flattened, with retrally curved striae. 



The species very closely resembles, and is probably identical with, an 

 undescribed form from the Chemung group of New York ; being similar 

 in size, form, and surface-markings, as well as in the solid axis and form of 

 the callus of the inner lip. It diffe'rs in the surface-markings from any 

 described form with which we are acquainted. 



Formation and locality. — In limestone of Devonian age, at Treasure 

 Hill, south of Aurora Mine, White Pine District, Nevada. Associated 

 with Strophodonta Canace, Rliynchonella JEmmonsi, Paracyclas peroccidens, 

 and other Devonian forms. Collected by Arnold Hague, esq. 



EOSSILS OF THE WAVERLY GROUP. 



RADIATA. 



Genus MICHELINA D'Kon. 



MiCHELINA Sp. 1 



Plate IV, fig. 19. 



Among the fossils received from Dry Canon there occurs a worn speci- 

 men of tliis genus, composed of tubes which vary from an eighth of an 

 inch in diameter to nearly or quite twice that size. The corallum seems to 

 have been highly convex, but not hemispherical in form, with few but 

 rapidly diverging tubes of moderate size. The specimen is imbedded in the 

 rock so as to expose the lower part of the tubes cut transversely. The 

 walls have been quite thick at this point, but become much more attenuate 



JJM 2-k 



