194 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



original description by the following, the result of an examination of the 

 additional material : — Corallum aggregate, forming large masses some- 

 times a foot and a half across and over a foot high, composed of upwardly 

 directed, flexuous, subcylindrical corallites that increase rapidly by lateral 

 calicinal gemmation from a single parent corallite. As a result of their 

 mode of growth from a small basal beginning, the corallites are somewhat 

 divergent, those near the confines of the corallum sometimes growing 

 almost horizontally. Corallites strongly and irregularly annulated, grow- 

 ing close together, frequently touching each other, their coherence being 

 often strengthened at the points of contact by an increased development 

 of the ridges of growth, or from want of space they may be closely pressed 

 against one another for some distance. Mature corallites varying in 

 diameter from 1 or 2 to over 3 cent., the young ones beginning with an 

 average breadth of about 5 mm. and growing upward beside the old stems 

 with a very slow increase in size. Epitheca thin, complete, showing 

 minor, transverse growth markings. Inner structure vesicular, similar to 

 that of C. vesiculosum from which this species apparently differs only in 

 its aggregate form." (Lambe, 1899 ) 



Localities and formation. — Abundant in the Corniferous limestone of 

 Ontario ; Rominger mentions its occurrence in large clusters in the 

 Hamilton group of Thunder Bay. 



Cystiphyllum sulcatum, Billings. 



Cystiphyllum sulcatum, Billings. 1858. Rep. of Progress for 1857, Geol. Survey of Canada, 

 p. 178, 

 •' " Billings. 1859. Canadian Journal, new series, vol. IV., p. 136. 



Nicholson. 1874. Palseon. of Ont., p. 38, pi. VI, fig. 7. 

 " " Rominger. 1876. Geol. Sur., Mich., Foss. Corals, p. 138, pi. L, 



lower row, left-hand figures. 

 Hall. 1876. Illus. Dev. Foss., pi. XXXII, figs. 16-20. 



" Corallum simple, short, turbinate, much curved, expanding at the 

 rate of between forty and forty-five degrees from the minute sharp 

 curved point upwards ; cup oblique, the lower margin being on the side 

 of the lesser curvature, moderately deep, and nearly regularly concave, 

 the bottom covered with obscure coarse rounded radiating ridges ; a shallow 

 rounded groove or fossette extending from the centre to the higher 

 margin, and in some specimens two others much less distinct, radiating 

 to the sides at right angles to the main groove. Exterior encirclt d by 

 obscure undulations, and longitudinally striated by the rudimentary 

 radiating septa. The vesicular structure consists of irregular sub-lenticular 

 cells, from half a line to two lines in width • length of the convex side, 

 from one inch and a half to three inches, the usual length appears to be 



