133 NOTES ON THE FOSSILS OF ONTAEIO. 



tabiilse. Lastly, Astrceophyllum is distinguislied from Cannapora. 

 Hall, by the possession of a columella, and the apparent absence of 

 tabulae. 



52. AsTR^OPHYLLUM GRACILE, Nicholson and Hinde. This being' 

 the only known species of the genus, the generic characters form pai't 

 of the specific description. In addition to these characters, however, 

 the corallites are cylindrical, and about three quarters of a line 

 in diameter, placed at distances apart of two lines, less or more. 

 The calices are expanded, about two lines in diameter, deep, with a 

 prominent columella. The septa are from twenty-six to thirty in 

 number, unequally developed, the greater number apparently reach- 

 ing the centre. The mural expansions are nearly horizontal, from 

 two to four in the space of two lines measured vertically, placed at 

 the same levels thi'oughout the mass. At the last formed surface, 

 the calices project sliglitly above the layer formed by the coalescerit 

 mural expansions ; and this layer is traversed by radiating ridges 

 corresponding with the septa of the corallites. The calices, however, 

 are circumscribed by very distinct and well developed walls. 



The upper surface of the coz'al somewhat resembles, on a small scale, 

 that of Heliophyllum colligatum, Billings ; but the mural expansions 

 and costal radii are confluent,'and are not marked off for each corallite 

 as they are in the latter. The mural expansions are variable in numbei', 

 sometimes very close, at other times remote. Owing to the silicifica- 

 tion of the specimens, it cannot be determined what are the characters 

 of the free edges of the septa, nor whether rudimentary tabulae may 

 not be present, though -no signs of the latter can be detected. In 

 Heliophyllum colligatum, on the other hand, there is a well marked 

 central tabulate area. 



Locality and Formation. — Common in the Niagara Limestone, 

 Owen Sound, 



53. Cannapora ANNULATA, Nicholson and Hinde, Corallum aggre- 

 gate, composed of numerous slender cylindrical corallites, which form 

 flattened expansions or crusts, and are united together by exothecal 

 growths. Corallites from half a line to nearly one line in diameter, 

 usually the former, nearly in contact, about four or five in the space 

 of two lines. The corallites are strongly annulated with close-set 

 annulations, which are developed into so many mural expansions 

 which unite together contiguous tubes. About four of these annula- 

 tions and expansions in the space of one line. Tabulae well developed 



