88 Canadian Record of Science. 



POTAMOGETON NATANS, Linn. 



Enderby, B.C., and Shuswap Lake, B.C. (Jas. M. Mac- 

 oun.) Griffin Lake, B.C., and Kevelstoke, B.C. {John 

 Macoun.) Not before recorded from British Columbia. 



POTAMOGETON PAUCIFLORUS, Pursh. 



Revelstoke, B.C., 1890. (John Macoun.) Not before re- 

 corded from British Columbia. 



BOTRYCHIUM LANCEOLATUM, Angst. 



Near Niagara Falls, Ont. (R. Cameron.) Not before found 

 in Ontario. 



Preliminary Note On The Limestones Of The 

 Laurentian System. 



By Elfric Drew Ingall. 

 Geological Survey, Ottawa. 



In view of the attention which is now being directed to 

 the above mentioned subject, in connection with the work 

 of the Geological. Survey of Canada in the Laurentian area 

 lying north of Ottawa, it is deemed a fitting time to record 

 the observations and conclusions of the writer on the ques- 

 tion above denoted. 



These observations were made whilst studying the mode 

 of occurrence of the phosphate deposits of the county of 

 Ottawa, Province of Quebec in the years 1888, 1889 and 

 1890, and have not before been presented to the public 

 owing to the pressure of other duties in connection with 

 the supervision of the division of Mineral Statistics and 

 Mines of the Geological Survey. A fuller and more com- 

 plete statement of results must even yet await the evidence 

 to be adduced from a microscopical study of the very com- 

 plete series of rock specimens collected. 



At the commencement of the investigation with a view 

 to prevent any prejudice in observation special care was 

 taken to avoid any preconceived theoretical bias and the 



