Canterbury and Westland. 469 



To this subject of great practical importance I have already alluded 

 on page 58, when speaking of my report, written in 1863, on the 

 possibility of obtaining a supply of artesian water for the City of 

 Christchurch, and in my report on the Formation of the Can- 

 terbury Plains in 1864, when the borings had been crowned by such 

 excellent results, I offered further observations on the natural process 

 by which such ample supply of pure water has been stored up. 

 There have been several causes in operation to form in the Christchurch 

 district inclined porous beds, enclosed between impermeable strata, by 

 which the water is retained — if not stored in a basin — and is compelled 

 to now downwards until it finds means of escaping. It is evident 

 that for Christchurch and its neighbourhood, the bottom of the former 

 greater extension of Lake Ellesmere, filled up by silt, sands, fluviatile 

 and turbary deposits, underlying that city, is the source from which 

 the greatest portion of the artesian water supply is derived. Part of 

 these beds have therefore been deposited in the form of a basin, in. 

 which artesian water is generally obtained with some degree of certainty. 

 Tor those artesian wells however situated to the east of the former 

 eastern shore of that lake, the water can only be derived from gently 

 inclined littoral beds, having been formed below the surface of the sea. 

 That this is the case is conclusively shown by the depth the borer has 

 to go before reaching the water retaining stratum, lying near Eiccarton 

 at 54 feet, whilst near the sea-coast it is only reached at 136 feet. It 

 is natural that the deposits filling up such a considerable portion of 

 the former Lake Ellesmere extension, according to the seasons or the 

 advance of the deltas of rivers, or having been formed on the bottom 

 or along its shore, must all be of a very different character. 



Moreover, below the lacustrine beds, there also exist a number of 

 layers formed in an arm of the sea, once surrounding an island (now 

 Banks' Peninsula), formed of shingle, sand, clay and ooze ; these in 

 their turn would offer the necessary conditions for the formation of 

 water retaining beds. It has been successfully demonstrated that 

 below the stratum from which in Christchurch the usual flow of 

 artesian water is obtained, one or more of these beds exist, containing 

 also an abundance of water, which when tapped, rises to a higher 

 level than the former. Thus, to give a few instances, at the North 

 Town Belt, water was first obtained at a depth of 76 feet, having only 

 a surface flow ; the same well continued to 136 feet, gave a splendid 

 supply rising six feet higher. At the Whately road public well the 

 water was reached at 74 feet, with scarcely a surface flow, but when 



