Page:Proceedings of the Royal Society of London Vol 60.djvu/541

Rh work to sink trial pits on the line of the portage, one of these, situated 70 feet from the high-water mark on the seaward face of the reef, was sunk 12 feet through sand and blocks of coral, when operations were brought a close owing to the influx of sea-water at high tides. Two other pits were then commenced nearer the sea and a little to one side (north) of the portage, at the margin of the solid platform of rock, which extends down to the growing edge of the reef and which is covered by the sea at high-water. These passed through sand and fragments of coral. In the most northern of the two pits the sand was somewhat consolidated, and so, proceeding a few yards further north, as far in that direction as it would have been possible to transport our machinery, we opened another pit, which was sunk for a depth of 11 feet through fragments of coral, crystalline coral limestone, and partly consolidated sand. The bottom of the pit was 2 feet below the seaward margin of the reef, and as we were not inconvenienced by an influx of sea-water and Ayles was of opinion that the rock would “ stand,” wo decided to make our new venture at this spot. Taking into consideration the difficulties of transporting our apparatus, I do not think a more favourable locality could have been chosen; it was close to the veryedge of the rocky platform, which is so hard that Darwin, speaking of a similar platform in the case of another reef, says t; I could with difficulty and only by the aid of a chisel procure chips of rock from its surfaceand as near the sea as it was prudent or even possible to go. Indeed, we had at first some doubt as to whether our pumping pipes would t; live ” in the surf of the ocean margin, and feared that the high-water spring tides might inundate the shaft; our fears in these respects, hovrever, proved to be groundless.

Captain Field and myself were impressed with the need of additional boring apparatus, and he proposed that Ayles should g-o to Sidney to see if it could be procured. I gave much anxious consideration to this project, and discussed it with my colleagues, Messrs. Hedley and Gardiner, and with Ayles. The information I received from Ayles was not encouraging. He stated that we should require a complete equipment of lining tubes from 10 inches down to 2± inches in diameter, that 10-inch tubes were not to be had in Sydney, and that even if we succeeded in obtaining all the