24 CONTRIBUTIONS TO CANADIAN PALiEONTOLOGT. 



a thickness of 2 or 3 inches. The corallites, as seen in vertical sections 

 radiate upward and outward from the basal nucleus with a spiral twist 

 and emerge obliquely to the surface ; they are thin walled throughout 

 their length, subpolygonal in transverse section, about 1-5 mm. wide and 

 •9 mm. high, generally with a broadly arched convex upper wall, one or 

 two somewhat concave lower walls and two short, straight, side walls, 

 with modifications of these. The obliquity of the corallites to the 

 surface and their compression are subject to much variation, those that 

 are most oblibue showing the greatest amount of compression. The coral- 

 lites undergo no change at the surface, they end abruptly without expand- 

 ing and without any thickening of their walls, the calyces being subpolygonal 

 and of the same shape and size as the corallites in the interior of the 

 corallum. Mural pores of moderate size, occurring in the sides of the walls 

 of the corallites, not numerous. Tabulae complete, placed at irregular 

 intervals. The inside surfaces of the walls of the corallites, as shown by 

 natural exposure through weathering and by means of sections, are studded 

 ■with numerous small squamulse arranged in longitudinal rows, those of 

 oae row alternating with those of the next, in the manner so usual in cer- 

 tain species of Devonian Favosites. On the basal surface of the corallum 

 the thinness of the epitheca permits of the shape of the corallites. which 

 here radiate outward almost horizontally from the centre, being clearly 

 seen. 



Of not infrequent occurrence in the Hamilton formation of Ontario, 

 and also found in the Corniferous limestone, as is evinced by a specimen 

 in the collection from Cayuga, Ont., collected by J. DeCew. 



Alveolites squamosa, Billings. 



Alveolites squwniosus, Billings. 1860. Canadian Journal, new series, vol. V. , p. 257. 



n Rominger. 1876. Geol. Sur. Mich., p. 41, pi. XVI., figs. 



3 and 4. 



Corallum in the form of irregularly shaped expansions, attached by 

 the centre of the base, sometimes 5 or 6 inches in diameter and 

 about 1 inch thick. Often a much greater thickness is attained by the 

 growth of additional layers of coral, one above the other. Upper 

 surface irregular, generally more or less convex, lower surface flat, pro- 

 tected by a thin, somewhat concentrically wrinkled epitheca, in which 

 the lateral outlines of the corallites radiating outward can be seen. 

 Corallites thin walled, compressed, very oblique to the surface, from '5 

 to 1 mm. broad and about -25 mm. high ; in transverse section they are 

 broadly arched above, and concave on either side of the centre below. 

 The interior of the corallites is studded with numerous sharply pointed 



