90 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



Peotarba vetusta, Hall. (Sp.) 

 Plate v., figs. 8, 8a. 



Porites ? vetusta. Hall. 1847. Palason. of New York, vol. I. , p. 71, pi- XXV. , figs. 5a, 56. 

 Protarea vetusta, Milne-Edwarda and Haime. 1851. Polyp. Foss. des Terr. Palasoz., p. 



208, pi. 14, figs. 6, 6a. 

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



II n Billings. 1866. Cat. Sil. Foss. of Anticosti, p. 32. 



Protarea vetusta, Nicholson. 1875. Pal^on. of Ont., p. 9 and Geol. Surv. of Ohio, vol. 

 II., p. 221. 



Corallum thinly incrusting, with a thickness of from 1 to 3 mm., cover- 

 ing an area 2 or 3 inches across; by the growth of one layer upon 

 another a thickness of about 10 mm. may be attained. Calyces shallow, 

 circular or subpolygonal, from 1 to 1-5 mm. in diameter, nearly touching 

 or from -5 to 1 -5 mm. apart, with twelve stout septa whose inner ends 

 combine to form a pseudocolumella having the appearance at the bottom 

 of the calyces of a number of tubercles. Between the calyces at the 

 surface are numerous subpolygonal openings, from one to five or six in a 

 straight line between adjacent calyces ; these become contracted a little 

 below the surface and are continued vertically downward as parallel 

 narrow tubes with thick walls. The structure, as seen in longitudinal 

 sections immediately below the calyces, is obscure and not definitely 

 defined from the surrounding tubules, but the spaces between the septa 

 are apparently crossed by independent transverse dissepiments which are 

 not of the nature of true tabulse. The tubules are crossed by horizontal 

 tabulae at rather close intervals. The rounded, exsert ends of the septa 

 at the edges of the calyces, together with the tubercles at the bottom of 

 the calyces and the presence often of tubercles in the intercalicular areas, 

 give the surface of the corallum a granular appearance. 



Occurs in the Trenton formation at and in the vicinity of Ottawa, Ont., 

 in division I of the Anticosti group, Anticosti, and in the Hudson River 

 formation in Manitoba. The specimens in the possession of the Geological 

 Survey were collected at Ottawa by Dr. Van Cortlandt, at Ottawa, by 

 H. M. Ami, 1882, and oh the Castor River near Castleman, county of 

 Russell, Ont., 1884, near Douglas, county of Renfrew, Ont., 1896, by R. 

 W. Ells and L. M. Lambe, those from Anticosti at Junction Cliff by T. 

 C. Weston, 1865. Nicholson mentions its occurrence (op. cit.) in the 

 Trenton limestone at Peterborough, Ont. The specimens described by 

 Hall are from the lower part of the Trenton formation at Watertown, 

 JeflTerson county. New York. It has been recognized from the lower beds 

 of the Hudson River formation at Stony Mountain, Manitoba, by Mr. 

 Whiteaves, but is not known to occur elsewhere at this horizon in Canada, 

 although it appears to be a not uncommon fossil in the Cincinnati group 



