CANADIAN FOSSILS. 57 



examined with the large ten-fingered fragments found in the Trenton 

 limestone. 



Explanation of Figures. Plate VII. 



Figure la. View of the posterior side of G. priscus. 

 " 16. Anterior side of the same specimen. 

 " Ic, Id., le., If. Columns found associated with la. 



Locality and fo7-mation. — One small perfect head collected at the 

 upper mouth of the cave at the fourth chute of the Bonnech^re, in 

 the County of Renfrew, in the Black River limestone. Fragments 

 of the heads and columns apparently referable to this species are 

 common in the Trenton limestone at Ottawa. 



Gltptocrinus eamulosus, Billings. 



(G. Ramulosus, Report Geological Survey of Canada, 1856, page 258.) 



Description. — The cup of this species very much resembles that of 

 G. priscus. It is covered with smooth plates, and the primary and 

 secondary rays are strongly keeled, but the base is broader, the basal 

 plates smaller in proportion to the size of the body, and there are 

 twenty free arms springing from the margin instead of ten, as in G. 

 priscus. The arms also are several times bifurcated at various dis- 

 tances from the top of the cup, while those of the former species 

 remain single to their extremities ; the pinnulae are in two rows, and 

 from one-fourth to three-fourths of an inch in length ; the ossicula of 

 the arms are very thin, and interlock with each other so deeply that 

 each seems to extend completely across, giving the appearance of 

 but a single series of joints where in fact there are two. Near the 

 base of the arms there are two joints in about one line, but higher 

 up there are from four to eight in the same length. The arms are 

 regularly rounded on the back, and comparatively slender, being 

 scarcely more than one line in diameter at the base of the largest 

 specimens. In the specimens examined four of the plates of each of 

 the secondary rays are included in the general test of the body. The 

 column is round, and at the base of the cup the large projecting 

 joints are thin, sharp-edged, and crowded close together ; they gra- 

 dually become farther apart as the distance from the base of the cup 

 increases, until at length they are from one to three lines removed 

 from each other. Between these large joints the column is composed 

 of very thin plates with crenulated margins, the projecting teeth of 



