385 



into the lake decreases, the level of the lake falls to about 

 3 feet (i m.) above mean tide. The cause of the higher 

 level of the lake waters relative to mean sea level is due to 

 the constricted nature of the outlet of the lake and to the 

 fact that besides the great volume of sea water entering 

 the lake twice each day there is also an additional large 

 amount of fresh water to be discharged. 



The level of high tide in St. John harbour varies between 

 10 feet and 14 feet (3 m. and 4-2 m.) above mean tide. 

 The waters of the lake rise with the tide only 15 or 18 

 inches (0-38 or 0-46 m.), therefore at high tide during the 

 latter part of the summer, the water in the St. John channel 

 at Suspension bridge stands 6 to 10 feet (i-8 to 3 m.) 

 above the level of the lake and as a result of the contracted 

 and shallow nature of the channel at the upper falls, the 

 waters there fall inwards. During other portions of the 

 day when the tide level sinks below the lake level, the falls 

 are reversed in direction and the waters fall outwards. 



The general configuration of the constricted channel 

 at Suspension bridge is sufficient evidence to indicate 

 that it is not of normal origin. Kennebecasis lake pre- 

 sents many of the general characters of a dammed body of 

 water. The lake and the contiguous lake-like expansions 

 of the St. John river occupy a series of depressions that are 

 portions of valleys belonging to two systems, one of which 

 follows a northwest-southeast course, and the other a 

 northeast-southwest course. The channel of the St. 

 John below Suspension bridge follows a northeast course 

 and therefore belongs to one of the above systems. The 

 lower channel of the river is apparently continued by the 

 depression traversing St. John city and known as the Valley. 

 At Suspension bridge, the depression occupied by the mouth 

 of the river abruptly ends, being cut off by a high ridge from 

 a valley extending some miles to the southwest. It is 

 not improbable that the dividing ridge is composed of 

 unconsolidated material of Glacial and post-Glacial age 

 and that at one time the valleys now heading in this ridge 

 were continuous. 



The lake of the lower St. John, whose bottom in places 

 lies nearly 200 feet (60 m.) below sea level, has probably 

 been formed by the empounding of the waters of the drain- 

 age system by dams choking the old outlet or outlets. 

 These dams are presumably of Glacial or post-Glacial 

 age. Forced to seek a new outlet, the waters for a time 



35063— I2A 



