DEVONIAN ROCKS OF CANADA WEST. 135 



reaching the centre ; transverse diaphragms turning downwards on 

 approaching the margin ; two to four in one hue. In some of the 

 coraUites the walls are so thin and closely united that no separation 

 can he ohserved, hut in others of the same cluster an outer area is 

 distinctly visiljle. There is usually a circular space in the centre of 

 the corallites, half a line or a little more wide, into which the radiating 

 septa do not penetrate, often, however, they reach the centre. The 

 young corallites sometimes spring from the side of the parent with a 

 slender base, and curving upwards immediately become parallel with 

 those of the whole group. In large colonies frequent instances may 

 be seen where instead of this lateral budding a bifurcation takes place, 

 both branches being of the same size. In large groups, owing to the 

 numerous additions of young, the corallites diverge slightly, as if 

 radiating from a point. The colonies are from six inches to several 

 feet in diameter, and large blocks of stone are of frequent occur- 

 rence, which are penetrated at right angles to the stratification by the 

 closely crowded stems. 



Locality and, Formation. — Rama's farm, near Port Colborne, and 

 in various localities in the townships of Walpole, Oneida, Cayaga, 

 and "Wainfleet, in the Corniferous limestone. 



Collectors. — A. Murray, E. Billings, T. De Cew. 



Several specimens in the Cabinet of the Canadian Institute at 

 Toronto. 



DiPHTPHTLLUH STBAMHTETJM (Billings.) 



Description. — Corallum forming large masses of cylindrical tubes 

 averaging two lines in diameter, and either so closely aggregated as 

 to be nearly in contact, or separated from each other by intervals of 

 from one to five lines, the distance varying in different clusters and 

 in different parts of the same. Sometimes numerous single tubes 

 occur scattered through the rock, which were probably derived from 

 some disintegrated group. The tubes are either straight or flexu- 

 ous, smooth, or annulated by short encircling folds of growth, the 

 surface striated longitudinally by the outer edges of the septa. 

 These latter are about forty in-number, and do not reach the centre. 

 The transverse diaphragms are well developed, slightly convex in the 

 centre, and appear to be suddenly turned down on approaching the 

 margin. The outer vesicular area is thin, seldom exceeding one- 

 sixth of the whole diameter. The central area altogether occupied 



ijW^.' 



