3l6 APPENDIX 



Mr. Billings described the genus in his " Report 

 on Canadian Fossils" (1861-64), taking A. profundus ^ 

 from the Lower Cambrian of L'Anse ^ Loup, on the 

 Labrador coast, in the first instance, as the type. 



A few years later, my attention was attracted to 

 this species by specimens presented to me by Mr. 

 Carpenter, a missionary on the Labrador coast, and 

 which Mr. Billings kindly permitted me to compare 

 with his specimens in the Museum of the Geologi- 

 cal Survey, collected by the late Mr. Richardson, at 

 L'Anse ^ Loup, in Labrador, in what were then 

 called Lower Potsdam rocks. Slices of the speci- 

 mens were made for the microscope, when it 

 appeared that, though they had the general aspect 

 of turbinate corals, like Petraia, etc., they were quite 

 dissimilar in structure, more especially in their 

 porous outer and inner walls and septa (see Fig. 5, 

 p. 35). Yet they could scarcely be referred to the 

 group of porous corals known in much later forma- 

 tions and in the modern seas. Nor could they be 

 referred with much probability to Sponges, as they 

 were composed of solid calcareous plates, which, as 

 was evident from their textures, could not have 

 been originally spicular. One seemed thus shut up 

 to the conclusion that their nearest alliance was with 



