DEVONIAN ROCKS OP CANADA WEST. 129 



edged and sometimes imbricating or folding over in an upward 

 direction. The septal striae on the exterior are very numerous, 

 there being six in the width of two lines, where the diameter is an 

 inch and a-half, and five in the same width, where the diameter is 

 two inches. The cup, in a specimen one inch and a-half in diameter, 

 is three-fourths of an inch in depth, and exhibits the free edges of 

 eighty-two radiating septa ; the cone is one-fourth of an inch in 

 height, but appears to have been higher. Another specimen, two 

 inches in diameter, has eighty-four septa ; and a third, two inches 

 and a-half in thickness, exhibits ninety-seven : the septa, therefore, 

 appear to vary in number between eighty and one hundred. There 

 is a septal foasette, the place of which is usually indicated in worn 

 specimens by an obscure angular longitudinal ridge. The longitu- 

 dinal septal striaj on the surface are double the number of the prin- 

 cipal septa. The external area is only about one or two lines in 

 thickness, and composed of cells which in worn specimens have a 

 rectangular opening on the surface, and are either of the width of 

 the spaces between the principal septa, or only half that size when 

 they are subdivided by the thin rudimentary septa. 

 ■ Small specimens of all sizes, up to five inches in length, which 

 appear to be the young, are common ; the very large ones, of one 

 foot or more, being not so plentiful. The species is closely allied to 

 C. coniseptum, which occurs in the mountain limestone in England, 

 hut is more strongly annulated and the septa more numerous. Some 

 of the specimens are nearly straight, but in general they are much 

 twisted in different directions and occasionally subject to rather 

 abrupt diminutions in the diameter. 



Locality. — 'Rama's Farm, and in many places in the County of 

 Haldimand ; Corniferous limestone. 



Genus Biotheophtllum.— (Billings.) 



Generic characters. — Corallum, simple, turbinate or cylindrical. 

 Internal structure, consisting of a central area occupied by flat, 

 transverse diaphragms, an intermediate area with strong radiating 

 septa, and an outer area in which there is a set of imperfect dia- 

 phragms projecting upwards, and bearing on their upper surfaces 

 rudimentary radiating septa. A thin complete epitheca and a septal 

 fossette. G-eneric name from Gl-reek BXoj^pds. 



This genua differs from Clisiophyllum in having the diaphragms 

 #at. 



