MHBE ] CANADIAN PALiEOZOIC COBALS. 89 



are frequently very obscure and difficult to see, although apparently a 

 complete amalgamation does not take place. Corallites from about 1 to 2 

 mm. in diameter in different specimens, but often exhibiting a considerable " 

 variation in size in the same individual. Tabulae complete, flat or 

 slightly concave, from four to six occurring in a space of 2 mm.; they 

 are also apparently present in the interspaces, but a little closer together 

 than those of the corallites. Septa twelve in number in mature corallites, 

 in the form of longitudinal blunt ridges, equally developed and extending 

 but a very short distance, about 2 mm. beyond the walls toward the 

 centre of the corallites. The calyces are shallow, wiih the septa mode- 

 erately distinct ; the intercalicular spaces are also visible at the surface. 



Hudson River formation. — At Snake Island and (loose) at Traverse 

 Point, Lake St. John, Que., J. Richardson, 1857, at Wreck Point, Anticosti, 

 Que., J. Richardson, 1856, and at Cape Smith, Lake Huron, R. Bell, 1859. 



The smallest specimens from Lake St. John are not more than 1 inch 

 or IJ inch broad and 1 inch high, other specimens are intermediate in 

 size between these and a large one that is 5 inches broad and nearly 3 

 inches high. 



This species originally referred to Golumnaria, has been assigned to the 

 above genus, although it dijGfers in having the walls of the corallites of 

 only a moderate thickness, instead of being extraordinarily thick. In the 

 Silurian Fossils of Girvan, pi. I., in the figures illustrating L. favosa, 

 McCoy, sp. the great thickness of the walls is not so very apparent, 

 especially in fig. la. In L. Goldfussi the septa are equal, always twelve 

 in number, and the tubular spaces between the corallites form a marked 

 feature of some of the specimens, viz., those in which the corallites are 

 circular. These interspaces appear to have tabulae, a feature which, if 

 taken with the cylindrical form of the corallites and the number of the 

 septa, suggests an approach to the genus Heliolites. The retention of this 

 species in the genus Lyopora would necessitate a slight amendment of the 

 original generic description. 



Genus Peotarea, Milne-Edwards and Haime, 1851. 



(Polyp. Foss. des Terr. Palseoz., p. 146.) 



Corallum incrusting ; corallites upright, opening at the surface in 

 adjacent, shallow, rounded calyces ; walls of the corallites not clearly 

 defined ; septa about twelve in number, stout, combining to form a thick 

 pseudocolumella ; interseptal spaces crossed by horizontal dissepiments ; 

 tubules occuping the spaces between the corallites, thick-walled, narrow, 

 with numerous, complete, horizontal tabula and without septa ; calyces 

 tuberculous at the centre and at the edge. 



