102 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



diameter of corallites from two to five lines, in general about three and a 

 half lines. The transverse diaphragms are not visible in the specimens 

 examined. The walls of the separate corallites are thick and concentric- 

 ally wrinkled.' This species is now represented in the museum collection 

 by a single specimen, labelled. in the handwriting of Mr. Billings, which 

 consists of a portion of a corallum with corallites that are circular when 

 free or almost polygonal when crowded together ; it unfortunately does 

 not show the septa, but tabulae are clearly distinguishable. Judging 

 from the manner of growth of C erratica, the presence of tabulse and the 

 stated presence of septa, the writer is inclined to believe that the descrip- 

 tion of C. erratica was based on imperfectly preserved specimens of C. 

 rugosa, and that the two species are identical, especially in view of the 

 fact that out of a number of examples of the latter species only one shows 

 the septa at all, but fortunately in this case very well." (Lambe, 1899.) 



Trenton formation. — Lake St. John, Little Discharge, Blue Point, Que., 

 J. Richardson, 1857; near Blue Point, A. R. C. Selwyn and J. Richard- 

 son, 1870 ; 2 miles south of Blue Point, W. McOuat, 1871 ; all the speci- 

 mens are silicified, and the structure is best seen where weathering has 

 taken place. Also at Lower Fort Garry, about 1 9 miles below Winnipeg 

 on the Red River, Manitoba, four specimens, one collected by Donald 

 Gunn in 1858, the other three by T. 0. Weston in 1884. 



The specimens from Lower Fort Garry have their structure well pre- 

 served and are, in the writer's opinion, clearly referable to Billings's 

 species. 



CoLUMNARiA CALiciNA, Nicholson. 



Plate VL, fig. 4. 



Favistella calicini, T!iioho\son. 1874. Rep. Brit. Ass., Trans, of 'sections, p. 89; and 



1875, Pateon. of Ont., p. 24, figs. 9 a, b. 

 Columnaria Hertzeri, Rominger. 1876. Geol. Sur. Mich., Toss. Corals, p. 90. 

 Golumnaria calicina, Nicholson. 1879. Palseoz. Tab. Corals, p. 197, pi. X., figs. 2, 2a. 



This species was described by Nicholson from specimens obtained from 

 the Hudson River formation at the Credit River, Ont.; it is represented 

 in this museum by specimens from the typical locality, as well as by 

 others from the same geological horizon at Cape Smyth, Lake Huron, 

 and from the Hudson River of Anticosti. 



Specific characters. — Corallum, attaining at times a diameter of over 

 15 cent., composed of corallites that may be either free and circular in 

 section or aggregated and polygonal or subpolygonal in section. The 

 corallites may be to a great extent free from the beginning of the growth 

 of the corallum, or they may only attain a circular form at a later stage 



