48 CONTEIBUTIONS TO CANADIAN PALAEONTOLOGY. 



Fletcheria incerta, Billings. (Sp.) 



Plate I, figs. 8, 80 and 9. 

 Columnaria incerta, Billings. 1859. Canadian Naturalist, vol. IV., p. 428, figs. 1 and 2. 

 Corallum in the form of irregularly shaped, somewhat hemispherical 

 masses composed of long, cylindrical corallites that proceed upward and 

 outward, subparallel to each other, from a basal centre. Corallites from 

 •75 to 1 -5 mm. in diameter, up to a distance of slightly over 1 mm. apart ; 

 although usually circular in transverse section they may become sub- 

 circular when in partial contact or polygonal when crowded together, the 

 walls of individual corallites always remaining distinct from those of con- 

 tiguous ones. Tabulse numerous, flat or slightly convex or concave, 

 from -5 to 4 or 5 mm. apart. Septa, apparently spiniform, very minute. 

 The corallites have a complete epitheca faintly marked transversely by 

 lines of growth. 



Locality and formation. — Mingan Islands, Island of Montreal and 

 near the city of Ottawa. Chazy limestone. 



Collectors. — Sir y^. E. Logan, J. Richardson and E. Billings. One 

 specimen from St. Charles Island, Mingan Islands, collected by J. Rich- 

 ardson, in 1860, is fully 4 inches in height. 



In transverse sections of the tubes the writer has seen what appear to 

 be very small spiniform septa. He has had difficulty in satisfying him- 

 self as to whether the increase in growth of the corallum is due to lateral 

 or calicinal gemmation, but the combination of characters is thought to be 

 more in accord with those of Fletcheria than with those of any other 

 genus. 



Dr. Nicholson* is of the opinion that Vermipora, Hall (stated by Rom- 

 inger to have mural pores) is most nearly allied to, if not an actual 

 synonym of Fletcheria. 



Genus Nyctopora, Nicholson. 1879. 



(Palseoz. Tab. Corals, p. 182.) 



" Corallum composite, massive, of polygonal corallites, which radiate 

 from the base of the spheroidal corallum, to open on its upper surface, and 

 are in complete contact throughout their entire length. Walls of the 

 corallites thin, and so completely amalgamated that no trace whatever of 

 the original lines of division between the tubes can be detected. Mural 

 "pores numerous, small, in more than one series, occupying the sulci between 

 the septa. Septa in the form of marginal vertical ridges, which extend 



* Palseozoio Tabulate Corals, p. 70. 



