CANADIAN PALAEOZOIC CORALS. 



10 



1875, one specimen (a portion of a large mass 1 foot in diameter) ; at a 

 number of localities at the southern end of Dawson Bay, and also at St. 

 125 on the east side of Lake Winnipegosis, J. B. Tyrrell, 1889; and at 

 Monroe Point, Lake Manitoba, J. B. Tyrrell and J. F. Whiteaves, 1888. 

 These specimens are preserved in the dolomitic limestone of this region. 



Mr. E. Billings and Professor Nicholson have expressed the opinion 

 that Favorites Gothlandica is common to the Silurian and Devonian forma- 

 tions of Canada. It was on the strength of these determinations that 

 Mr. Whiteaves identified the Manitoba specimens of F. Alpenensis with 

 F. Gothlandica. Dr. Rominger however, has shown that the Silurian 

 species may be distinguished by their spiniform septa and the Devonian 

 forms by their squarnulae. 



Favosites Billingsii, Rominger. 



Favosites Billingsii, Rominger. 1876. Geol. Sur. Mich., Foss. Corals, p. 28. 

 Favosites Gothlandica, Nicholson. 1879. (not F. Gothlandica, Lamarck. 1816.) 

 Palaeoz. Tab. Corals, p. 46, but quoted on p. 56, from Arkona, 

 Ont., as var. Billingsii, Rominger. 

 Favosites Gothlandica, var. Billingsii, Whiteaves. 1889. Contr. to Can. Palaeon., vol. I., 

 pt. II., p. 121. 



Corallum growing in broadly expanding discs, of varying convexity 

 above, with a small central base of attachment ; under surface rather flat 

 with irregular concentric ridges and covered by an epitheca marked by 

 minute concentric lines. Corallites prismatic, unequal, with an average 

 width of about 2*5 ram. ; in some specimens a few dispersed corallites 

 occur that are noticeably larger than the others and attain a maximum 

 diameter of about 4 mm. Pores generally in one sometimes in two rows 

 in the sides of the corallites ; about *33 mm. in diameter and surrounded 

 by a raised margin. Tabulae complete, horizontal, numerous, in distance 

 apart varying from less than 1 mm. to 2 or 3 mm. and frequently exhibit- 

 ing a varying number of marginal depressions. Squarnulae present in 

 small numbers only. Where the exterior of a corallite is exposed in a 

 fractured surface it is seen to be delicately striated in a transverse 

 direction. 



The largest specimen seen by the author is 10 inches in diameter and 

 3 inches high but Dr. Rominger in his original description of the species 

 records a diameter of 3 feet. 



Abundant in the Hamilton formation of Ontario. 

 * Contr. to Can. Palaeon., vol. I., pt. IV., p. 258, 



