wmbe. ] CANADIAN PALAEOZOIC CORALS. 83 



downward bent edges of the tabulae. Septa apparently represented only 

 by a slight thickening of the walls of the corallites. 



Lower Helderberg group. — L'Anse a la Vieille, Baie des Chaleurs, west 

 of fault, 1 J. Richardson, and one mile east of mouth of Little Cascapedia 

 River, Baie des Chaleurs, R. W. Ells, 1883. 



Plasmopora petaliformis, Lonsdale. (Sp.) 

 Plate II., figs, 9, 9a. 



Porites petalliformis, Lonsdale. 1839. In Murchison, Silur. Syst., p. 687, pi. 16, figs. 4, 4a. 

 Plasmopora petaliformis, Milne-Edwards and Haime. 1851. Polyp. Foss. des Terr. 

 Palseoz., p. 221. 

 M ii Milne-Edwards and Haime. 1855. Brit. Foss. Corals, p. 253, 



pi. LIX., figs. 1, la—c. 

 Heliolites sparsus, Billings. 1865. Canadian Naturalist, new series, vol. II., p. 428. 

 Billings. 1866. Cat. Sil. Foss. of Anticosti, p. 31. 



Corallites 2 mm. in diameter or slightly under, circular, with twelve 

 equal lamellar septa, almost extending to the centre ; distant from each 

 other from about 1 to 4 mm. Between the corallites are numerous 

 irregularly polygonal tubules, rather unequal in size, from four to eight 

 occurring in a line between adjacent corallites. The tabulae of the coral- 

 lites are horizontal and placed close together, from three to five in a 

 space of 1 mm. The tubules are occupied by more or less convex or con- 

 cave tabulae which interfere with the regularity of the walls of the 

 tubules ; the latter appear in longitudinal sections as parallel, somewhat 

 irregular lines running in a vertical direction to the surface. The Can- 

 adian specimens examined have the structure well preserved, but they do 

 not show the external form ; according to Lonsdale and Milne-Edwards 

 and Haime the corallum is hemispherical. 



This species differs from Plasmopora follis, Milne-Edwards and Haime 

 in having larger and more distant corallites, with a larger number of 

 ccenenchymal tubules in the interstitial spaces. 



Niagara formation and Lower Helderberg group. — Anticosti group, 

 division IV,, Anticosti, two miles west of Chicotte River, J. Richardson, 

 1856 ; l'Anse a la Vieille, Baie des Chaleurs, ? J. Richardson. 



Genus Lyellia, Milne-Edwards and Haime. 1851. 



(Polyp. Foss. des Terr. Palseoz., p. 226.) 



Corallum massive, of various shapes, globular, pyriform or hemispheri- 

 cal, sometimes tuberose or discoidal, also in the form of flabellate or lobate 

 expansions with calyces on both sides ; corallites cylindrical, varying in 



