78 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



MEAN SEA LEVEL AT ST. JOHN 



(Abstract of paper by E. T. P. Shewen, C.E.; read March 1st, 1893.) 



The determination of mean sea level at St. John furnishes a fixed 

 datum from which to calculate tidal fluctuations, besides elevations 

 for geological, geodetic, and physiographic studies. 



Last year this determination was made from an analysis of two 

 years of tidal observations, recorded by the Thomson gauge at Reed s 

 Point, covering the period between April 1894, and May 1896. The 

 gauge is in charge of Mr. D. L. Hutchinson of the St. John Observa- 

 tory ; and the records obtained have been carefully reduced to datum 

 by Mr. W. Bell Dawson, Engineer in charge of the Tidal Survey. The 

 resulting values of mean sea level, and of high and lowwatei, ordinary 

 spring tides, have been referred to a bench mark cut for the purpose 

 on the southeast corner of the Custom House. (See Bull. N. H. S. of 

 N. B., No. XIII, p. 109.) 



Mean sea level is 41.65 feet below the bench mark, or 12.67 feet 

 below high water- ordinary spring tides, the range being 25.33 feet. 



City Levels. — City levels are taken from forty feet below assumed 

 (extreme) high water. The elevation of any point above mean sea 

 level is the reduced level, according to city datum, minus 25.49 feet. 



Intercolonial Railivay Levels (St. John to ijhediac). — The elevation 

 of any point above mean sea level is the reduced level, according to 

 I. C. R. datum, minus 86.95 feet. 



European and North American Railway Datum (now I. C. R.) 



Feet. 



High water spring tides, St. John (Buy of Fundy).. . . ion. on 



Mill street 104.95 



The Marsh 102 



Lawlor's Lake 162 



Rothesay ( 9 miles from St. John) 107 



Hampton ( 22 " 



Susses ( 44 " " 



Penobsquis ( 51 " " 



Mom-ton Station (89 " " 

 Sackville (128 " 



Shediac Wharf , rail level (Northumberland Strait) 93.30 



High water, Shediac ( lOS miles from St. John) 89.30 



117 

 1 55. .">:> 

 154 



i:<ii.74 

 116.25 



