CONSTRUCTION OF RAILWAYS.

55

D.—No. 6b

wide, as it would embrace part of the flax land between the terrace and the river, and also an overflow channel and island between it and the main river bed. This terrace is there broken through (near Mr. Macfarlane's house), but gradually forms again and approaches the river bed at the termination of the overflow channel, which here re-enters the main river bed. At this point the terrace now forming the main river bank is higher than at any other point, and forms the second site below described ; this is never flooded in the highest floods. This formation continues for a few chains, the bank then gradually lowers and becomes liable to overflow in high floods ; this liability increasing gradually all the way down to the site of the present bridge, offering no chance of a safe crossing below the point just described, notwithstanding the great temptation offered to select one by the extreme narrowness of the river at a point about a mile below, but where the capacity of the channel, there confined between high clay banks, is totally inadequate to carry off the flood water. Sites. The first of the sites mentioned is at Ashley township, where for a few chains along the bank we have choices of a crossing-place nearly opposite the road leading from Bangiora, and passing near the schoolhouse in Ashley township. Prom this the railway would be carried on a descending gradient nearly parallel with the Upper Sefton Eoad, and contouring the termination of the low spurs of the downs, across which the road now runs ; this line would join the line of the Railway Eeserve between sections 8,755 and 2,420. The ground between the end of the present surveyed line near Eangiora and the Ashley would present no difficulties ; the bridge at this site would be about 3,432 feet long (52 chains). The second site is about lg milo above the present bridge, where the river bed is about 25 chains wide. Between this and the end of the surveyed line at Eangiora there are no difficulties, the ground being dry and flat, and proceeding northwards there is a fair stretch of regular even ground to Saltwater Creek, and across the upper part of the old Sefton township, clear of swamps, joining the first-described line a short distance before entering the line of the Eailway Eeserve. The peculiar features of the two sites, and their connecting lines, may be described as follows : — The approach on the south side to the upper site is tolerably even but rather low, requiring embankments. The section of the river bed is very irregular, the water flowing in three main channels, with high stretches of shingle between, the stream impinging forcibly against the north bank and evidently destroying it, not only on the probable line of bridge, but for some distance below and above, where the line of bank is very irregular and broken, and would evidently require protective works in the event of a bridge being built. The banks are too low in themselves to receive a bridge, and would require embanking, say for a few chains, to reach the inclined ground on which the road lies. The railway line then would, as before described, follow generally the direction of the line of road and the contour of the hilly ground for about five miles, in which provision should be made for the escape of the numerous streams flowing from the downs, amounting, on the road line, to ten bridges, varying from Gto 20 feet, and 12 culverts, 2to 3 feet. The number of these latter might be reduced, say one-half, in the construction of a railway, but the bridges would be increased materially in length in order to cross, in workable curves, the heads of the swamps which penetrate at intervals into the hilly ground. Some of the spurs would require heavy cuttings to reduce the sharpness of the curves. It will thus be seen that in this portion of the line would be a number of curves, bridges, culverts, and cuttings with a generally descending gradient. The level of the bridge would be about 64 feet above that of the termination of the surveyed railway line at Eangiora. The approach to the lower or second site would, on the south bank, be by regularly falling ground to a good safe high bank, needing very little embankment. The river bed here is of regular basin-like shape, with sloping banks, not being destroyed. The north bank, as before described, is high and dry above the reach of any flood, requiring little or no embankment; and the line beyond would traverse gradually falling even ground to Saltwater Creek, which would require bridging to a considerable extent with a succession of small spans at a good elevation, to receive the natural flow of the creek, with that, in addition, which in high floods escapes from the upper part of the Ashley. The upper part of Sefton township could be crossed on level firm ground, and the land beyond, to the junction with the Eailway Eeserve, is of the same character. The whole distance from the Ashley to the reserve would require a moderate amount of embankment. The question relating to drift timber, which may only be expected in very high floods, will affect the two sites in a different manner : the upper one will be in most danger from this cause, as all the drift timber must pass through it; whereas it has been shown that a very large proportion of it is discharged into the side overflows and lodged there, leaving a comparatively small amount to pass the lower site. On this account, therefore, I should say that the upper site would require wider spans than the lower, possibly in the proportion of CO or 70 feet to 40 or 50 feet at the lower site, and consequently at an increased cost. As regards the future safety of the two sites, I have already stated that the upper one will require protection, which the lower one at present does not appear to require; and the upper one will be in most danger from drift timber. The lower site, it may be averred, is in danger of being left altogether by the river changing its bed above the site and discharging itself into Saltwater Creek. I cannot think this is at all probable, as the overflow takes place over such a large extent of low land, and is not confined to one or two narrow outlets, but is spread in a comparatively thin sheet of water over a large area, doing very little damage to the surface. It is true that provision must be made to allow for the passage of this increased flow of water in Saltwater Creek, as before described; but with this provision, I should have no fears for the safety of this line. I may now state that the result of the examination recorded above was to impress me with a con-