Art. XXXVIII.—Notes on an Artesian-well System at the Base of the Port Hills.

By S. Page, with Analyses by E. B. R. Prideaux, B.A.

[Read before the Philosophical Institute of Canterbury, 27th February, 1901.]

Last year it came to my knowledge through Mr. T. E. Cutler, of Gebbie's Valley School, that flowing artesian wells of considerable depth had been obtained inside Lyttelton Harbour, at and near Teddington; also that similar flowing wells, all more or less warm, existed on the other side of Gebbie's Pass.

The wells vary in depth from about 70 ft. to 290 ft.; in temperature from 65° to 84° Fahr. One or more rise as much as 20 ft. above the surface, and they extend in one direction as far as the ocean-beach and in the other from the north side of Gebbie's Valley round the foot-hills as far as Little River.

Seeing that the wells extended over such a considerable area, it was at first thought possible that the supply might be connected with the artesian system of the plains. If that was so, however, the presence of the wells at Teddington would tend to show that the alluvial system of the plains extended under the hills.

To test the point, samples were obtained from six representative wells, through the kindness of Mr. T. E. Cutler, and analyses of these by Mr. E. B. R. Prideaux are appended.

From Mr. Miller, of Gebbie's Valley, who sunk the greater part, if not all, of these wells, I learn that inside Lyttelton Harbour the wells pass through clay, freestone rock, sand, and in one case rubble, but no shingle. On the other side of the hills, in addition to sand and clay, waterworn shingle was constantly met with, in beds as much as 50 ft. in thickness. In one well, on the spit between Lake Ellesmere and the sea, no clay was found; sand and shingle only. In this case water was met with at 50 ft. and the flow did not improve to the extreme depth reached—212 ft. In other cases, where beds of clay were interposed, the flow increased with the depth.