44 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



ing spaces are crossed by horizontal diaphragms somewhat stouter than, 

 but at about the same distance apart as, the tabulae and showing the 

 same irregularities of growth. The longitudinal ridges appear on the 

 outer surface of the walls, in the spaces between the corallites, as costse ; 

 they pass over the edges of the calyces and connect with correspond- 

 ing ridges in contiguous corallites. The costal ridges at the surface, 

 when the corallites are separate, extend radially but a very short distance, 

 about -5 mm. beyond the confines of the calyces, leaving the surface of 

 the corallum between the corallites smooth ; this intercalicular surface is 

 at times marked by obscure, contiguous, polygonal outlines surrounding 

 individual corallites, but no trace of this demarcation is seen in transverse 

 or longitudinal sections. The edges of the calyces are but slightly 

 elevated above the intercalicular surface and in worn specimens appear 

 as smooth raised rings. No definite traces of a basal epitheca have been 

 detected. 



Calapcecia Canadensis occurs in the Birdseye and Black River, and 

 Hudson River formations. In the former it is found in the Ottawa district 

 and in the latter on the islands at the north end of Lake Huron, on Snake 

 Island, Lake St. John, Que., and on the Island of Anticosti; it is also 

 found in the Galena-Trenton limestone of the Lake Winnipeg district and 

 of the region to the north. Specimens have been collected at the follow- 

 ing localities and have been available for study and comparison. In the 

 Birdseye and Black River, near Ottawa, Ont., E. Billings, at Hull 

 (Ottawa), Que., J. Stewart, 1886 ; Paquette's Rapids, Ottawa River, T. C. 

 Weston, 1872 and 1881, hill south of Clear Lake (loose), county of Ren- 

 frew, township of Sebastopol, R. W. Ells and L. M. Lain be, 1896, near 

 Point Blue, Lake St, John, Que., A. R. C. Selwyn and J. Richardson, 

 1870. In the Hudson River, north side of Drummond Island, Lake Hurom 

 A. Murray, 1847, Cape Smith and Rabbit Island, Lake Huron, R. Bell, 

 1859, Wreck Point, Anticosti, J. Richardson, 1856, west side of Gamache 

 {or Ellis) Bay, Anticosti, T. C. Weston, 1865, Snake Island, Lake St. 

 John, J. Richardson, 1857. In the Galena-Trenton, Lower Fort Garry, R. 

 Bell, 1880, T. C. Weston and A. McCharles, 1884, East Selkirk, Manitoba, 

 T. C. Weston, and A McCharles, 1884; Big Grindstone Point and Deer 

 Island, Lake Winnipeg, J. B. Tyrrell, 1889, first limestone exposure south 

 of Long Point, Lake Winnipeg, D. B. Dowling, 1891, junction of the 

 Churchill Rivers (drift), R. Bell, 1879, Markham Lake, Telzoa River, 

 lat. 62° 44', long. 103°, J. B. Tyrrell, 1893, Herb (Wekusko) Lake, Dis- 

 trict of Saskatchewan, J. B. Tyrrell, 1896, also Fort Churchill, Hudson 

 Bay (Cambro-Silurian), J. B. Tyrrell, 1894. 



The large number of specimens of this genus obtained of late years, and 

 now in the collection of the survey, have convinced the writer that C. 

 Canadensis and C. Huronensis cannot be retained as distinct species 



