FOUNDATIONS OF GUY.

Star (Christchurch), Issue 16848, 26 September 1922, Page 7

FOUNDATIONS OF GUY.

WHAT LIES UNDERGROUND? STRANGE EVIDENCE FROM DEEP WELLStrange evidence of what- lies under the city lias been disclosed by the operations of well sinkers at the corner of Tonic's and Swann’s Streets. North Beach. They have sunk a well 508 ft deep, and the varying layers through which the bore has passed provide matter of much interest geologically. DETAILS OF BORE. \ The ground passed through by the : 3in well was as follows: ; From Layer.

j Water rose 26ft above kerb September j ]9. 1922. INTERVIEW WITH AIR R. SPEIGHT. Mr IT. Speight, curator of s the Museum, said he was very interested in the record provided by the sinking of this well- As far as he knew it was j the deepest well that had yet been sunk in the New Brighton area. There would be two points on which he would like to have information, namely whether the water from tho well contained salt and whether the well was affected by the rise and fall of the tide. The water from some wells in the New Brighton area contained salt. This did not always mean that- the water was unfit for drinking. Tn fact in some cases there was so little salt in the water that it made it quite pleasant to drink. On the other hand some of the wells gave water that was quite brackish. As regards the wells being affected by the rise and fall of the tide, Air Speight said that this applied particularly to the shallow well? in the New Brighton area. the flow of water from them varying very considerably with the rise and fall of the tide. HOW THE STRATA VARY. Mr Speight pointed out that the above table showed that in this well clay and Hand predominated over shingle. This was always the case in .wseTls •sunk in land under the lee of Banks Peninsula. He showed the reporter a diagram showing how, starting from Kaiapoi, the amount ot shingle decreased tlie nearer one got to New Brighton, which is well under ; tlu* lee of Banks Peninsula- ; The diagram of one well sunk at Kaiai poi showed that the pipe had passed j through shingle practically all the way, whilst in some of the wells sunk at New Brighton hardlv any shingle had been met with. Veils sunk at. places beyond Kaiapoi, such as Sefton, passed through shingle all the way. In the same way. at Islington shingle predominated, and gradually decreased tlie nearer the well was sunk to New Brigli ton, as. for- instance, nf Wainoni. An interesting fact pointed out by ATr Speight was that one stratum, say. of clay, had been found at practically the same depth right from Kaiapoi to New Brighton. SECRET OF ARTESIAN SUPPLY. -Mr Speight said that it was the alternate layers of clay, sand and shingle which made the artesian wells around Christchurch. In one well at Kaiapoi. which had been sunk to practically the same depth ;is the above well, the water rose very little above the surface, because tho well was sunk mostly through shingle. SINKING OF THE LAND. The fact that timber was found «t a depth of about 500 ft was interesting, ! said Mr Speigh*. It may have been growing timber, and in that case »; ■ would show that the land had sunk to a depth of 500 ft since the trees grew. However, lie nresumed that the timber in question was a log lying flat, and not the stump of a tree, as lie did not think the pipe would have passed through a stump. Tn that case, tlie log was prob | ably drift wood, and the presence of the timber would indicate that the bed in i which it was found was laid down in ; shallow water and had subsequently sink to a depth of from -100 ft to 500 ft. : Round about Christchurch timber and | peat bad been found at a greater I depth than 500 ft, For instance, peat | had been found at Hornby at a depth 1 of 700 ft. Another interesting fact, Mr Speight ! said, was the finding of sea-shells at a i depth of about 490 ft. This, of course, I indicated that at one time the sea flower! over the bed in which they were I found, and that subsequently this bed i had sunk.

ft. ft. ft. 1 to 70 Beach sand . . . .70 70- 95 Blue sand 25 95-185 Blue clay 40 135-155 Blue shingle . . . 20 155-170 Brown shingle (water rose 1ft above kerb . . .35 170-234 Yellow sand .... 64 234-242 Brown shingle (water rose 9ft above kerb) .... 8 242-268 Blue clay 26 266-36.5 Brown shingle ('water rose 12ft above kerb; flow at depth of 275ft. 295ft, 820ft and 356ft) .... 97 365-400 Yellow sand . . . .35 400-414 Very hard brown shingle (no water) U 4i 4-450 Yellow ea-nd . . .36 450-494 Blue clay and sea-shells .. 14 194-496 Timber 2 496-408 Very hard brown shingle . 2 498-508 Brown shingle, loose . .30 Total depth .... 508