CANADIAN FOSSILS. 5T 



Explanation op Figures. Plate III. 



Fig. la. The plates of the calyx spread out ; the dotted lines which extend from the top 



to the bottom indicate the course of the arms. 

 Fig. 16. Plates of the genus Echino-encrinites figured here for comparison. 

 Fig. d. Anterior view of a perfect specimen of G. multiporus. 

 Fig. E. The left side of the same specimen. 

 Fig. F. The dorsal or posterior side of another specimen. 

 Fig. c. The right side. 

 Fig. g. The apex enlarged. 

 Fig. i. The base. 



Fig. n. A specimen with the column attached, anterior view. 

 Fig. L. One of the rhombs enlarged. 

 Figs, g & k. Sections shewing the depth to which the partitions of the rhombs entered. 



Locality and Formation. — Trenton limestone, City of Ottawa, 

 Montreal and Beauport. Only fragments have been found at the 

 latter two places, and all the perfect specimens, about sixty, were 

 collected from a piece of shale about two yards square and one or 

 two inches in thickness. There is good reason to believe that they 

 lived and died upon this spot. The shale was a layer between two 

 beds of limestone, the lower of which was partly composed of the 

 detached plates of this species. Imbedded in its surface were several 

 perfect specimens among the fragments. The shale which covered 

 it was full of individuals with their columns and delicate pinnulse 

 attached. It is quite clear that they could not have been at all 

 drifted about the bottom after death, otherwise they would at least 

 have lost their columns and pinnulas. It is more probable that they 

 formed a little colony, growing on this spot at a considerable depth, 

 and in clear water, and that the shale consists of a deposit showered 

 down upon them from a superficial current, literally burying them 

 alive. 



Collector. — E. Billings. 



VIII. GrLTPTOCYSTITES LOGANI, BillingS. 



Plate IV. Figs. la-h. 



{Geological Survey of Canada, Report, 1856, p. 282.) 



Description. — Length of large specimens one inch and a-fourth ; 

 diameter eight lines ; cylindrical, obscurely five-sided, abruptly trun- 

 cated at the summit ; base slightly rounded ; each plate ornamented 

 with from three to seven exceedingly elevated, somewhat thin, sharp 

 ridges, which radiate from the centre to the sides; spaces between 

 the ridges smooth, or very minutely striated concentrically ; calycinal 



