p.—No. 6a.

Coast Line —Length, 3 miles 3 furlongs 1 chain. £ s. d. Excavations, 125,539 cubic yards, at Is. 4d. ... ... ... ... 8,369 5 4 34,698 cubic yards, at 2s. 6d. ... ... ... ... ... 4,337 5 0 Accommodation Bridge ... ... ... ... ... ... 150 0 0 Culvert in Mechanics Bay for Saw Mill ... ... ... ... ... 150 0 0 Smaller Culverts and repairs of existing one ... ... ... ... ... 210 0 0 Two Road Bridges, about ... ... ... ... ... ... 600 0 0 Two small Tunnels, lined with timber, 313| yards, at £7 ... ... ... 2,194 10 0 Fencing and draining, 243 chains, at £3 ... ... .., ... ... 729 0 0 5,962 yards of Permanent Way, at 16s. ... ... ... ... 4,769 12 0 £21,509 12 4 Summary. £ s. d. Domain Line ... ... ... ... ... 14,409 0 4 Tunnel Line ... ... ... ... ... 21,394 5 8 Coast Line ... ... ... ... ... 21,509 12 4 Notes. 1. No provision is made for pitching the sea embankments in case the excavations at Fort Britomart, &c, do not yield material of sufficient tenacity, and in sufficient quantities for the purpose, so that if pitching becomes necessary, the extra cost would be nearly the same for the Domain and Tunnel Lines, but the increased cost for this purpose would be large for the Coast Line, on account of the greater extent of the sea embankment. 2. There is great uncertainty in the cost of the tunnel, and considerable risk in its execution. 3. The tunnel would make the station for Parnell costly and inconvenient. Henry AVriog, 15th August, 1871. Engineer-in-Charge.

No. 3. Waikato Railway.—Memorandum by Mr. Blackett. The annexed report (15th August, 1871), accompanied by two tracings, is forwarded by Mr. Wrigg for the purpose of enabling the Government to decide as to which of the three lines between Newmarket and the wharf at Auckland shall be adopted. The lengths and estimates are as follows, viz.: — £ s. d. Domain Line, 2 miles 3 furlongs 1 chain ... ... 14,409 0 4 Tunnel Line, 2 miles 1 furlong ... ... ... 21,394 5 8 Coast Line, 3 miles 3 furlongs 1 chain ... ... ... 21,509 12 4 The feeling being decidedly against the Domain Line, on account of it passing through a favourite place for recreation from end to end, the choice may lie between the Tunnel Line and Coast Line. It will be seen that their estimated costs are nearly equal, and that Mr. Wrigg notes the risk of undertaking the Tunnel Line (on which I havo already strongly reported), and the consequent uncertainty of its cost. The objections to the Coast Line are, its extra length (one mile on a dead level), and the doubt that exists of the material of which the cliffs are composed, and which will be used in forming the embankment, being able to stand the wash of the sea or harbour. I think this need not be dreaded, as a good wide flat slope can at first be given to the embankment, which afterwards may be protected with hard scoria rock brought down from Newmarket at a small expense after the line is opened and applied to those parts needing protection ; it may be placed at random and not pitched, and will thus resist the action of the surf better, and cost very much less. 22nd August, 1871. J. Blackett, C.E. ■

Mr. Blackett, —Can you tell me whether the coast line would reclaim tidal land in Mechanics Bay, and, if so, what extent ?— \V. Gisborne, 24th August, 1871. Mr. Gisborne, —The plan shews that about 10 acres would be reclaimed in Mechanics Bay ; but I should not think that the full cost of reclamation is included in estimate. The bay, however, is very shallow, and ■would not require much filling. —J. Blackett, C.E., 24th August, 1871. Eor His Honor Mr. Gillies, —Would you favour me with your opinion on these alternative lines ? My own opinion inclines to the Coast Line.— W. Gisborne, 24th August, 1871. Looking to the relative cost of the Tunnel and Coast Lines, and their relative risks and advantages, I have no hesitation in giving my opinion in favour of the Coast Line.—T. B. Gillies, 26th August, 1871.

CONSTRUCTION OF RAILWAYS.

6