umbe. ] CANADIAN PALAEOZOIC CORALS. 103 



of growth, or they may form reticulated loops, not unlike a large Halysites, 

 or loose fascicles, with free corallites irregularly interspersed. The coral- 

 lites are from about 3 to 6 mm. in diameter, and the line of division 

 between them, when closely crowded together, is quite distinct. The 

 septa vary in number from about twenty-eight to thirty-eight, of which 

 one half pass to the centre or nearly so, the remainder are very short and 

 might easily escape notice. The tabulae are horizontal, entire and deflected 

 at the periphery. The outer surface of the corallites is strongly marked 

 by encircling lines of growth and longitudinal ridges. New corallites 

 seem to be reproduced by lateral calicinal budding. 



This species approaches very closely to Columnaria rugosa. Billings, 

 from the Trenton of Lake St. John, Que., indeed it is questionable 

 whether it would not be best to consider it as a variety of the latter 

 species. Its corallites have not such a free growth as those of the Trenton 

 form, and are, when crowded together, more decidedly angular and in 

 closer contact. In C. rugosa the corrallites are more generally circular 

 in section, even when aggregated, and the appearance of the corallum 

 suggests a somewhat stronger growth. 



Hudson River formation. — Cape Smyth, Lake Huron ; Credit River 

 at Streetsville, Ont., J. B. Tyrrell, 1888. The largest specimen from the 

 last named locality is over 10 cent, high and nearly 15 cent, across ; 

 the initial basal point is present and the divergence of the corallites, the 

 gradual growth of the corallum and the admixture of circular and poly- 

 gonal tubes are well shown. A slightly worn and evidently loose speci- 

 men labelled " East of White Cliff, Gamache Bay, Anticosti, J. Richard- 

 son, 1856," is probably from the Hudson River formation of this island. 



Columnaria disjuncta, Whiteaves. 



Columnaria ( Cyathophylloides) disjuncta, Whiteaves. 1892. Contr. to Can. Palaeon., 

 vol. I, pt. IV., p. 269, pi. XXXIV., figs. 3, 3a, 3b. 



" Corallum composite, consisting apparently of a colony of cylindrical, 

 straight or flexuous, ascending or erect corallites, which are separate but 

 sometimes partially in contact, or more or less closely aggregated ; 

 diameter of the corallites averaging about five millimetres, their mural in- 

 vestment single and external. Surface markings of the corallites un- 

 known, though in transverse sections there are indications of longitudinal 

 ribs, corresponding to the septa within. Calyces deep, with erect sides : 

 primary septa thirteen, simple, neither crenulated nor denticulated, very 

 thin, laminar and extending to the centre at and below the bottom of the 

 cup : secondary septa similar in number and structure to the primaries, 

 but reaching only half way to the centre. The only internal structures 



