68 CONTRIBUTIONS TO CANADIAN PALAEONTOLOGY. 



from -which the specimens were obtained. From this table it can be 

 seen that H. catenularia and its varieties range from the Black River 

 limestone at the base of the Trenton formation up to the rocks of the 

 Lower Helderberg group; and that the Black River limestone in eastern 

 Canada, the Galena-Trenton of theLake Winnipeg region, &c., in the west, 

 the Hudson River, Niagara, Guelph and Lower Helderberg formations 

 have their distinctive varieties. 



Mr. Whiteaves has drawn my attention to the fact that the chain 

 coral was collected (probably for the first time in North America) at 

 Drummond Island, Lake Huron, by Dr. J. J. Bigsby, in 1819 or 

 1820 (see p. 204 of the first volume of the second series of the 

 Transactions of the Geological Society of London, published in 1824). 

 Also that the next mention of Halysites as occurring in Canada, if not in 

 America, was made by William Henry Fitton, M.D., F.R.S., G.S., &c., on 

 p. 559 of appendix No. 4 to the " Narrative of the Arctic Land Expe- 

 dition to the mouth of the Great Fish River, and along the shores of the 

 Arctic Ocean, in the years 1833, 34 and 35, by Capt. Back, R.N., 

 London, 1836." In reference to the limestone fossils brought by Capt. 



Back, from Lake Winnipeg, Dr. Fitton says " There is also one 



specimen which, though not in good preservation, is doubtless a 



Catenipora or chain-coral, " The exact locality is not given, but 



the fossil is in all probability the same as one of the forms from Lake 

 Winnipeg or vicinity mentioned in the table accompanying this paper. 



Halysites catenularia, L. 

 Plate III., figs. 1, la, 16, 2, 2a and 3, 3a. 



The typical form as identified by United States and Canadian palseontologists under 

 this name, or that of Catenipora escliaroides, Lara., and 0. agglonierata, Hall. 



The most typical form of the chain coral, in the writer's judgment, 

 occurs in the Niagara formation of Ontario, at and near Owen Sound, on 

 Cockburn Island, and at Lake Temiscaming ; near the mouth of the 

 Saskatchewan River ; and in rocks of nearly if not the same age in Anti- 

 costi and near Donald, B.C. 



The specimens show a considerable variation in the size of the meshes, 

 within certain limits, as can be seen from the table of measurements; 

 tubules are present between the corallites, averaging about -5 mm. in 

 width, and having close set, almost at times vesicular, strongly arched 

 tabulae ; septal spines are well preserved in some specimens, in others 

 they are only indicated and at times not preserved. 



Specimens have been collected from the Guelph formation which are 

 possibly referable to the typical form ; they are preserved in the char- 



