1899] Lambe— Canadian Palaeozoic Corals. 249 



Locality and formation. — East River, Pictou, Nova Scotia, 

 collected by Sir J. William Dawson ; lower Carboniferous 

 formation. 



Phillipsastr.*;a Billingsi, Calvin. 



Pkillipsastrea gigas,Wi\\'\.ngs, 1859. Canad. Journ., vol. IV, new 

 series, p. 128 ; incorrectly identified with Arach- 

 nophylluni (Astrea?)gigas, Owen. 



" g^g<^^> Nicholson. 1875. Rep. Palasont. Prov. On- 



tario, p. J"]. 



" gig(^^(?)> Rominger. 1876. Geol. Surv. Michigan, 



Fossil Corals, p. 128, pi. xxxvil, fig. 4. 



" billingsi, Calvin. 1893. Amer. Geologist, vol. XII, 



p. Ill, pi. VI, figs. I and 2. 



Corallum composite, large, discoidal, more or less convex 

 above, rather flat below, formed of slightly divergent, confluent, 

 polygonal corallites, from about 2 to over 4 cent, in diameter, 

 that increase by marginal calicinal gemmation from a central 

 basal beginning ; attaining a breadth of over 40 cent, and a 

 height of nearly 12 cent. Basal surface covered by a concentri- 

 cally wrinkled epitheca. Corallites not bounded by a wall, their 

 septa meeting and becoming confluent with those of the neigh- 

 bouring corallites; opening on the upper surface in calyces having 

 a broadly convex, exsert reflexed circular rim surrounding a deep, 

 steep-sided pit measuring from about 8 to 10 mm. in diameter and 

 4 or 5 mm. deep. Septa well developed, numbering from about 

 forty to sixty, of two alternating sizes, the larger reaching the 

 centre and becoming somewhat twisted, or falling short of it, 

 the smaller not extending beyond the sides of the central pit ; 

 they are decorated on their sides by arched carinse curving 

 upward and inward and appearing on their free edges in the 

 central pit and reflexed calicinal margins as small transverse 

 denticulations. Tabulae, forming a narrow axial area, at times 

 well developed, flat at the centre, turned down at the edge, the 

 primary septa passing over them to the centre as carinae, at 



