MR. DOBSON'S REPORT ON THE WEST COAST ROUTE.

Press, Volume VII, Issue 799, 22 May 1865, Page 2

MR. DOBSON'S REPORT ON THE WEST COAST ROUTE.

Bailway Offices, Heathcote Valley, - May 15,1865. Sib, —I hare, the honor to report the.result of the survey of the dividing range between tbe head-, waters of the Harunui and Waimakariri. rivers, under*' taken in accordance with your instructions, and also to inform you of the steps which I have taken under these instructions for the construction of a bridle road through the gorge of the Otira. For the better understanding of my report it may be well to refer to the nature of my instructions, both ■written arid verbal (ccc appendix A). They were in substance as follows, viz :— To report on the practicability and cost of forming a bridle track through the Otira gorge. To examine and report upon any other pass which ' Mr. George Dobson (then engaged on an exploration of the dividing range) might consider supetior to that by. the Otira' gorge. To select the beet line of dray road through the dividing range; and to let a contract for, the formation of a bridle track on the selected luxe to Mr* John Smith, the contractor for the Craigieburn and Lochinvar roads; ," . - j. ' . Fending the preparation of the contract fd» f the bridle road, to employ the working parties to be Bent up by Mr. Smith upon the improvement of the Per* , ter's pass and Craigieburn roads, and to value the work so done on its completion} 1 " - : : \-_ ~ In accordance with these instructions I.left Ghnitf-: church March 15, and wafc occupied until ApnlA'" inclusive, in the examination of the dividing range. The result of this examination may be ttioi con* : cUely stated:— That the pass known as Arthur's pass, by toe :, valleys of the Bealey and the Otira, is the only Jeading out .of the Waimakariri, over which a «B»JU& road could "Be taken to the West Coast. That the cost of making a dray road Arthur's pass, although very considerable, less than half the amount that would be requirajWs|i> make an equally .good ro&d to the same point aJLjOyfes T<>ramakau by way of the Hurunui valley. m|^ That a good bndle track might by formed. m|||pij! weeks' time over Arthur's pass, which would be able at all times of the year except during tiet/rj'J'j freshes. ' - That a comparatively trifling amount of work jww|Ss suffice to make a dray track from the end of I«e s Pearson (where .the present! road turns towards JLochinvar,) ac far as the foot'of AnntnVV pass, a distance of ninety-three (93) mites from Chrietchureb, and eleven (11) miles from tb*junction of the Otira with the Teramakau; whilst tro tto- // Hurunui route, the dray track only extends to Waitohi gorge, a distance of fifty-eteat (68) »jbrc : from Christohurcb, leaving a length of sixty-one milee of road £6 be~ma3e to reach ttfe eameipaint, the 7 total saving of distance by the former route bring fifteen ;(15) milee. - , " _ • ' :, "i L- 4. Saving arrived at the foregoing conclusions, once ; commenced setting outfiielxnf, of bridle tnw.\."over Arthur's pass with a strong: furnished by Mr. Smith* At the same time I direct*! the contractor to form a. road through the of theyalieyof the Bealey, and to make *°™*'™ i **Jj°M at Goldney's saddlej between GraMmere of the Waimakariri, for the purpose of opening dray : track to the pass at the earliest. moment;- ■ • Lrfm "■ Ifc wa» my intention to hare made bac one, conassepp for the- whole work of the bridle track topsgjg& Arthur , * pass, a distance of fite and M df i gg2£& mace, bat an the 18dr of April I received informing mc that was oaia,W« take charge of the works, with two Targe paraajW men under the~4ireetion of Mr. W. Whale M&££%ffe E. Wright who v . were" prepared to lake under Mr. Thornton's direction. ' " ; -^^' I therefore divided the work at Arthttfe putting the length from the head of the *"rffiJSy| the head of the lower gorge of Uie Otira mto » Smith's, hand*, .andleaving. tae work m UW_«IJ W% gorge of the Otira to be set out bj M*. and let to one of the other cqntractore. .. Oα the 22nd of April Mr. Thornton Bealey, sad I then arranged with, bm tbatm*^

hand over the work remaining to be ~ T ~£sfy&*m the summit of Porter's pass and the b3t *° Messrs. White and Wright, and concentrate" tt| irfcele staff of men ajxm his work in Arthur's* - <JSm arrangement was carried into effect on "CjMttof^priL *?f Ktomed to Christchurch on the 25th April, |mtW Itr. Thornton in charge of the works, after contract to Mr. Smith for the whole of 2» week reonnred for the construction of a bridle ifaft faun the end of the new dray track to the head if the Lower Otira gorge. contract, a copy of which ie attached to this (appendix E), is based on fixed prices per bush clearing, draining, side cutting U[ inrtiP n "»Ci whilst the gullet cuttings are left to Iβ Measured and valued on their completion, it being isßoeeUe to ascertain beforehand the nature of the ' jirVtpbe cot through. fatal estimated amount of the contract is as BOTTTH BIDX OV SUMMIT. (Length, 1 mQe 67 chains.) Jffr*. prices ... £668 15 0 Wot, to be measured and "Shed 1300 0 0 ; •, £1968 15 0 '\ KOKTH SIDE OP BTTVXTr. (Length, 2miles 23 chains) Wofct«*fixed prices ... £796 0 0 Weak, to be measured and jabed 600 O 0 1296 0 0 Total estimated cost £3264 15 0 - ~. Total length, 4 miles 10 chains. v3fce whole of the track where it runs through jbath or serab is to be cleared ten (10) feet wide, the ~ infy •** *° drained and metalled six (6) feet vide, and the aide cuttings formed and metalled six - fg) fret wide on the solid. The gullet cuttings are | 10 |s ten (10) feet wide in the floor, the material - ftem the cuttings to be used in metalling the track » SB e*°fc **de to distances not exceeding three (3) - L dams average lead. ■ "i-Wift some trifling exceptions the bridle track is to - fte farmed on the h*ne of the permanent dray road, Jramtne head of the Bealey to the head of the Upper Ofira gorge. From this point to the head of the "~ Lower Otira gorge, a distance of about half a mile by fte permanent line, the bridle track turns with a . slotrp rise to the eastward, and after skirting the cluTs * wtoeh boimd die upper gorge, turns again in a west- - eify direction, and descends to the level of the river at tbe head of the lower gorge by a winding route

■long a leading spur; the distance by the bridle track Wag seventy-five (75) chains. Although this portion - «f ffae fine is not suited for a cart road on account of

ftfdwpMwi of the gradients, and the unavoidable ..slurp turns, it would be quite practicable to make use •fit for light dray traffic if it were made twelve (12) - fiat wide and the gradients eased by zigzags for a distase of about eighteen (18) chains, through which I bare not thought it necessary to do more than clear Sμ timber, the ground being sound and free from the Imlden and fallen timber with which the greater jmtt of the track is at present encumbered. \- jOb the line of bridle track the Bealey river will be fgnied three (S) times. The first ford is in the gorge *at lbs side of the proposed cart bridge. The descent -' to tins ford is by rockside cuttings four (4) feet wide, ::/sad s foot bridge has been thrown over the etream " rw* i **' lt J above the ford. The two (2) other fords are near the summit of the pass where the Bealey is -?'. m ff*"^"? i, Ibemain stream of the Otira is not crossed above ffti head of the lower gorge, and the only other stream sseoeed to the north of the summit is a tributary of tdfte Otira, which is seldom more than ancle deep exsa|Bl immediately after heavy rains. "iW&f tb* t/eTna °f the contract the track is to be made i&ftopaMe for driving stock by the end of May, and the g whole of the work is to be finished by the 14th of J-c;, An inspection of the section of Arthur's pass Iffflg. 10), and of the plan attached to the contract efatosadix c), will give a clear idea of the character > sad extent of the work included in the above contract. . .. . ■\ ' The staff of men and hones employed by Mr. preparatory to the letting of the contract, viz., K-fconi March 17 to April 27 (both inclusive), was as I TO ' Men. Packhorses Si week ... 29 ... 6 ... 1 2nd „ ... 48 ... 6 ... 1 r? Ui „ ... .55 ... 6 ... 1 - ■fch „ ... 85 ... 6 ... 1 t - BUmi n ... 97 ... 8 ... 1 -: Mr „ ... 119 ... 8 ... 1 The cost and description of the work done during ZJ&m period was as follows, viz:— r'Thpsjn and improvements on the ?'. Porter's pass road between the .-"■ Xbwai and Qraasmere (asperde--7 taued account appendix b) ...£843 0 0 Wort, commenced at Goldney's Saddle 100 0 0 "y-lfaaaißg dray track in the upper part of .. \ Jfwßealey Valley ...... 350 0 0 **ggJjP£!> exploring and cutting Q Q fitting Ibotroad oro Arthur's pass and ~ retting out Kne of dray road... .:. 180 0 0 o*aeeount of contract lor Bridle track 193 0 0 * £1746 0 0 Xfcne passed two Touchers in payment ; ; -of SkZmmt, to. i ... .;. ...£IOOO 0 0 746 0 0 U. - Total ... £1746 0 0 B k unnecessary that I should enter into any de--1 aantion of the works now in progress for the im- ' JMnmeent of the Gnujgiebnrn road, and the oonstrnc- :•_ *neof a- dray track along the south bank of the " *wsanatarin, as Mr. Thornton, the engineer in y?«haqp of these works, will report to you fully on this •djict. It js sufficient hen to state that their com. ;jgetiMwffl bring the head of the Bealey within a ~ Christehurch, and that except dur--7 Sag heavy floods there is no reason to apprehend any ■; obstruction to the traffic throughout the year, if road ~- parties are employed to attend to the necessary re- . |ai%*asto dear the summit of Porter's pass after -fcawy&D&ofsnow. ~ ~ - -She works required for opening a horse track from ; ft*n«th end of Smith's contract through the lower 5?- tiiQ ppen valley of the Otira, a distance of - T!** 0 ,, * «°d a-half miks. are of a very trifling char- . «*«, all that iat required being to lower the depth of i- »*t¥r *tthe finds by Uaeting out the boulders, which atpreaentdam up the stream, so as to give an in- - . rmaiuil width of waterway. At present the river has r 16 times, hut a great number of these oeangs nught probably be avoided by making short ■decuttmjs. . I estimate the cost of making safe finds •■4 eonneeting them by a track along the islands and ■age terraces, at £270. The work could be readily w«i * fortmght's time. _«ris improvement of the fords would render Hperfcetlyeafctoume paok-horeee or stock through the - except in times of flood, when the traffic might ItO W 4 ** ***• » four d *y ,L ¥or *• coaTeni * •„ •BCBofJbottravauon, I would recommend putting .. over the river as near the fords as practi- •*». These foot-bridges would each consist of a ■■a*'logadsed level on the upper aide, and bolted *owa«* each end with inch ecrewbdlts let into the •oßdrodt, abundance of writable timber on *• spot, and the cost should not exceed five (£5) P*mo4 for each bridge, say in all eighty (£80) P«m6«; this would bring up the total oost of the ««letrack through Arthur's pan to three thousand ace hundred and fourteen pounds fifteen shillings (£3614155.), as under, to. :— Batimated amount of contract ...£326415 O Bnda in lower gorge 270 O 0 Footbridges ditto.?. 80 0 Q £861415 O

Aβ I ehall presently have occasion to explain, the £2K. W * y ° f a road through the lower., gorge 3K*" c Otira, which shall not be subject to interrupS»n from floods, hjtfc building up retaining wails in the river bed, and ttias constructing a series of artificial terraces, conmcted by heavy cuttings through the projecting points of rock, the sides of the gorge being too precipitous to allow of forming a road by •carping the hill side in the ordinary nmnner. Aβ these retaining walla must be solidly backed up, whatever the nature of the road they are to carry, it will easily be seen that the cost of making a bridle road above the flood level would be little less than that of making a dray road, the difference being chiefly in the width of the rock cuttings. Until the Government are prepared therefore to continue the line of dray road down the valley of the Teramakau, I do not consider it is worth while to incur the expense of making a road above the flood level through the gorge of the Otira, as the'track will always be passable for horses when the Teramakau itself is fordable.

From the bottom of the lower Otira gorge to the Teramakau, a distance of about six (6) miles along an open river bed, no difficulty exists to taking either packhorees or stock

A sum of six hundred pounds (£600) spent in cutting through the timbered flats, and in making sidecuttinge where necessary to avoid the necessity of crossing the river, would probably be sufficient to make a very fair dray track as far as the junction of the Otira with the Teramakau.

Aβ Mr. W. Blake is now engaged in exploring the country for the purpose of ascertaining the best route between Hokitika and the junction of the Otira and Teramakau, I will only observe with regard to this portion of the road to the West Coast, that I am disposed to think from the description of the country given mc by returned diggers, that a track would be formed from the Teramakau, starting a little below the mouth of the Hopeakeoa, crossing into th« valley of the Arahura by a low saddle, and thence passing over low timbered country to the mouth of the Hokitika.

Before concluding this report, it may be desirable that I should briefly describe the character of the several West Coast passes, and that I should give an approximate estimate of the cost of making a dray road through the dividing range by the only routes at present known to be practicable, viz., the Hurunui saddle and Arthur's pass.

The first point to be noticed in regard to the central chain, is that it does not, as is generally supposed, present an unbroken line of watershed, but rather a series of peaks and broken ridges, separated from each other by deep ravines, and for the most part perfectly inaccessible.

The clue to this system of ravines and ridges is to be found in the fact, that the paltezoic rocks forming the main range hare been at a very earlj period subjected to intense pressure, the effect of which has been to crumple them up into huge folds, the upper portions of which have been removed, leaving the remaining portions of the strata standing up on edge, either in a vertical position or at very steep inclinations.

The strike of the beds, corresponding with the direction of the axes of the foldings, is tolerably regular, being generally about 27. 22 deg. E. (true.) It is important to observe that in the Waimakariri district as well as in the sourhern portion of the centra] chain described by Dr. Haast (see Gazette, VoL IX, No. XVIII), the rule appears to hold good which has been found to prevail in other mountain chains of similar formation, viz., that the greatest amount of denudation has taken place along the original ridges, which are now occupied by valleys, whilst the existing peaks and ridges are on the sides of former depressions.

This may be seen both at Arthur's pass and at the npper part of the Waimakariri valley, leading to Browning's pass. At each of these places the strata on the east side of the valley stand vertical or nearly so, whilst those on the western side have a northeast dip (see fig. 30), showing the general form of the folds to be as in the annefed sketch (fig. I.) In the npper part of the Otihake gorge," i;he strata on both sides of the valley have a north-east dip, the rocks on the western side in many places overhanging the water (see fig. 20, 21, 22, and 23). This appears also to be the case in the pass leading N. from the White river examined by Messrs. I Harman amd Browning. - The next feature to be noticed is the jointed structure of the rocks; although the' joints cross each other in all directions apparently without order, there are two systems of joints which are met with throughout the whole valley of the Waimakariri, and which have an important influence on the configuration of the passes. These are— Ist. A syetem of vertical cross joints at right angles to the stratification, and running in unbroken lines for great distances with such regularity that they might easily be mistaken for planes of stratification were it not for the frequent occurrence of beds of trap lock, the outcrop of which marks unmistakably the true bedding. 2nd. A system of joints more or less inclined to horizon, not running in parallel planes but arranged in a series of curves radiating from a common centre.

The effect of this system of jointing is to produce a certain rectangular arrangement in the plans and sections of the ravines, the rivers and watercourses running either on the strike of the beds or in the direction of the cross joints, or in a zigzag course, following alternately these two directions, as in the annexed sketch (fig. 2), which shows the character of the valleys connecting the Waimakariri and Teramakau, which have a general northerly direction, thus making an angle of about 22 deg. with the strike of the strata. ■<■..• In consequence of the vertical position of the strata, and the inclined position of what may be called, for convenience of description, the horizontal joints, the sides of the ravines present either sheer precipices or dangerous slips, according to the extent to which the rocks have been loosened by exposure to the rain and frost, and the result is that to form a road in side cuttings through any of these ravines is simply impossible. The only plan to be adopted is to blast away or tunnel through the projecting portions of the cliffs, and connect these cuttings by embankments either formed of etone or protected by stone walls, arid raised sufficiently above the river bed to secure the road from being overflooded during freshes (as shown in fig 3). In some places, asm the gorge of the Otihake, even: tiiis is impracticable from the numerous slips, along t which every winter large masses of stone detached from the clifiV by successive frosts, find their way to i the river bed below, felling with a force that would destroy any engineering works that might arrest their course. The only alternative would be to bridge over 1 these slips, leaving sufficient headway for the moving masses of <Z&ra; tut the cost of* road constructed in thie manner would outbalance the advantage to be derived from its construction. In addition to the foldings above described, the neks of the central chain have been subject to a variety of upheavals and dislocations which have resulted in the formation of a system of valleys, the direction of which is very remarkable, the principal valleys from the Teramakau, on the north to the Makarora, on the south radiating from a common centre, situated about fifty (50) miles to the north of Mount Darwin. (See map fig. 4). j It might naturally be imagined that these valleys would form passes through the dividing range,, but such is not the case, as with the exception of the Huxunui Talley, they do not extend through the western portion of the chain, but terminate in glaciers or are bounded bj high ragged precipices as is shown in the sketch of the range at the head of the Waimakariri. (Fig. 27.) The pass at die head of Lake Wanaka, explored by Dr. Haast, and of wtrieh a section is given (fig. 13), is no exception to' this general rule, as it only leads through the southern branch of the main chain into another valley running to the coast in a westerly direction, and bounded on ite northern ade by the any zangeu '

The pass is, however, a remarkable one, being the lowest of all the known passes between the east and west coasts, a circumstance which is probably due to the fact that the line of the valley coincides with the strike of the strata, whilst in the case of the Waiuiakariri the line of tie valley is at right angles to the stratification. The pas 3 has not yet been opened ever for fast traffic, but it will probably one day become a very import mt line of communication between the west coast of Canterbury and the northern part of the Otago province, and it appears desirable that a horse trunk should be opened through it with as little delay as possible, should it be found practicable to do so within a moderate cost.

Between Haast's pass and the head waters of the Rakaia it may be considered as settled that no pass whatever exists, Dr. Haast's surveys showing that the summit of the range is covered with perpetual snow.

It is probable that passes might be found out of the Rakaia, along which tracks might be cut which would enable stock to be driven over to the West Coast, but from the height of the mountains communication would be completely stopped by enow during the winter months, and the country is unsuited for dray traffic.

I think it would be very desirable to connect the Rakaia valley with the head of the Hokitika by a foot track, and would suggest the selection of the pass traversed by the late Mr. Henry Whitcombe (see figure 14), unless Mr. Browning's present exploration should result in the discovery of a better line. The saving of distance between Christchurch and the Hokitika township, as compared with the route by Arthur's pass, is however so trifling that I do not think it would be worth while at present to spend any large sum in an attempt to make a second horse track over this portion of the range.

Passing from the head-waters of the Rakaia to those of the Waimakariri, we still find a total absence of westerly passes. The tributary valleys at the head ofthie river lead in a northerly direction, over high saddles into deep and impassible ravines, apparently the sources of the Hopeakeoa, the main etream, known as the White river, coming from the south, out of a large glacier.

Browning's pass, which at first sight appears to offer a favorable route across the range, is at a lower elevation than the other saddles, but is inaccessible even on the eastern side, the so-called pass being cut off from the valley of the Waimakariri by cliffs having a total height of seven hundred and fifty (750) feet, whilst the only line along which a sidling could be safely cut to connect the valley with the top of the pass has a gradient of 1 in 3, and is quite unsuited for anything but a foot track. (See fig. 28, 29 aud 30). We now come to the consideration of the valleys between the Waimakariri and the Teramakau ; of these the Hawdon and the Poulter may at once be set aside as leading either to the gorge of the Otihake, through which not even a foot track could be made except at a fearful cost, or in to the upper part of the Teramakau valley, over saddles from which the descent is too precipitous for the construction of any useful road.

Of the two passes by the valley of the Bealey—viz., Arthur's pass and the Goat's pass—the latter may be dismissed from consideration on account of the elevation at which the range has to be crossed, although in other respects it is well suited far a stock-driving road, and could be opened for this purpose at a moderate cost.

We have, therefore, only two passes left to select from, viz., Arthur's pass and the Hurunui saddle, none other being known to exist in the northern portion of the province over which it would be possible to construct a dray road. The summit of Arthur's pass is a long, open valley, the highest point havirg an elevation of rather less than three thousand (3000) feet above the sea level.

The approach on the south side is by a gentle ascent, the line of road following the general inclination of the ground up to the summit. On the north side the valley is broken up into terraces stared with large blocks, "deposited by the glaciers of a past age. The upper terrace has been formerly a lake of considerable but from the melting of its icy barrier It is now little/more' than a swampy flat, intersected by numerous streams which filter through the moraines one hundred and fifty (150) feet below the level of the lake, and unite to form one of the tributaries of the Otira.

At the end of the open valley just described, the Otira falls one hundred feet (100 feet) or more into a basin about half a mile in length, bounded on the west bj cliffs, and on the east by slopes of loose shingle. This is called the Upper Otira gorge, and it is the descent from the open valley into this gorge tb»t forms the principal difficulty in constructing a road through Arthur's pass. I have already explained that a track can be formed which would be practicable for light dray traffic, by widening and improving the bridle road now in formation on the east side of the valley; but the only satisfactory solution of the problem is to construct a tunnel, as shown in the section (fig 10), to connect the upper and lower levels. It is impossible without detailed plans and sectione to state very closely what would be either the gradient or the length of this tunnel, but it may be safely calculated that the distance to be tunnelled through would not exceed one hundred and eighty (180) yards, and I have taken this length as the basis of'my calculations of the cost of the work. At the lower end of this basin the whole valley becomes contracted, and the river runs for a mile and a-half through a gorge, which, narrow at first, gradually widens out until at the junction of a tributary from the westward it ceases altogether, and the river runs through a broad shingle valley to its junction with the Teramakau. This is called the Lower Otira gorge. Through the upper part of this gorge the road would have to, be formed as already described, by building up retaining walls, and tunnelling through projecting points of rock ; but on the lower portion the sides of the gorge are less precipitous, and advantage may be taken of shingle terraces, islands and eloping hill sides j crossing the river where necessary by timber bridges, so ac to take advantage of the most favorable ground. Although a great body of water occasionally comes through this gorge, 1 do not consider that there is any difficulty in constructing a permanent road above the flood level if care is taken to maintain a proper width of waterway, and to avoid sharp turns or projections in the retaining walls. No detailed estimate can be made, of this work without preparing the contract plans, and taking out the quantities of bridging, blasting, and walling that may be required, but from the experience I have had of similar works, I consider that m y approximate estimate will be found to be very close to the actual value of the work.

The only other engineering work of importance on the Authur'e pass road is a bridge over the Bealey, which will be required to connect the terraces on the 1 eastern and western sides of the river, it being impossible, on account of the cross gullies, -to make the ascent of the pass entirely on either bank. I have prepared two designs for this bridge. No. 1 (fig. 86) is for a timber superstructure, resting on two wrougbt-iron arched ribs of one hundred (100) feet span. No. 2 (fig. 37) is lighter and less costly, end consists of iron lattice) girders eapported on wire ropes, the cables being crowed under the girders so as to form a diagonal bracing, and thus prevent the lateral oscillations, which is one of the great defects of j ordinary suspension bridges. I The track might be opened for traffic nine (9) .months after letting the contract. The tunnel would take some months longer, but it would be desirable to defer its construction until after the opening of the dray track, on account of the facilities which 'would be afforded for bringing plant and materials to the site of the works. „ The distance from Christchurch to the Teramakau by Porter's pass and Arthur's pass is one hundred and four (104) milee. Jt would, however, be desirable (should the overlan<l%*ffie justify the expenditure), to ayoid the eteep fcscrait of Porter's pass by forming a road through the gorge of This would reduce the length of the road Oy seven (7) miles, making the total distance firom ChrStchurch to the Teramakau only ninety-eeven (97) mfles, whether tii» route taken fb&owed the Coal Track on the aouth,

or the Lower Eyre road on the north side of that river. But as it would only lengthen the distance about four (-i) miles more to go through Kaiopoi, it appears to mc that it would be desirable to extend the proposed Northern Railway westward through Rangiora to Oxford, and to make a road thence through the gorge of the Waimakariri.joining the present track between Grassmere and Groldney's saddle. The total diet mcc by this route from Christchurch to the Teramakan would be one hundred and one (101) miles, and the completion of the road to the coast would hring Hokitiki within tnro (2) days' journey from Christ church.

For parties coming from the southern part of the province, the shortest route is by the Rakaia gorge and Lake Lyndon. This route is perfectly safe for horsemen and stock, and does not require any present expenditure. The distance from Timaru to the Teramakau by this track is one hundred and forty (140) miles.

Having thus carefully considered the difficulties and advantages connected with the construction of a road through Arthur's pass, it remains only to examine whether the Hurunui route presents any special advantages which should lead to its adoption in preference to that by the Waimakai-iri valley. The Hurunui saddle is considerably higher than the summit of Artnur's pass, and the upper part of the Hurunui valley is subject, like the valley of the Waimakariri, to occasional floods, fry which the traffic might be stopped ; but no part of the route involves work? of the heavy character required in Arthur's pass. On the other hand, of the sixty-one (61) miles intervening behind the end of the present 3ray track at the Waitohi gorge and the junction of the Otira and Teramakau, no leas than thirty-six (36) miles are over hilly sidling country, requiring an amount of rock cutting, walling, and bridging, which cannot be estimated to cost on an average less than two thousand four hundred pounds (£2400) per mile, or in round numbers eighty-six thousand pounds (£86,000). Assuming the remaining twenty-five (25) miles to cost on an average one hundred and sixty pounds (£160) per mile, the cost of the line from the Waitohi gorge to the Otira junction will amount, at a very moderate estimate, to ninety thousand pounds (£90,000), being nearly three times the estimated cost of the road by Arthur's pass ; nor is there any saving of distance to compensate for the increased cost of construction.

The distance from Christchurch by the Hurunui valley to the Otira junction is one hundred and nineteen (119) miles, or fifteen (15) miles longer than by Porter's pass, whilst from Timaru the , distance is two hundred and nineteen (219) miles, showing a saving of seventy-nine (79) miles in favor of the route by Lake Lyndon and Arthur's pass. Another point to be observed is that several miles of the Hurunui route would be on the Nelson side of the boundary, and a grave question arises as to the propriety of a Government executing public works beyond the limits of its jurisdiction. And it must be clearly understood that it is not to the interest of the Nelson Government to give any assistance to the Hurunui route, because a much more useful line of road can be made in the direction of the track already cut from theHanmer plairsto the Grey valley, which would connect the Hurunui plains with the valleys of the Waiau, the Mariua, and the Ahaura, whilst a branch line on the east side of Lake Brunner would connect this track with the Canterbury road leading down the Teramakau to the coast.

It would suggest, therefore, that instead of spending money upon the Hurunui track, which will not be used by the settlers north of the Hurunui, and which offers no advantages in point of distance over that by the Waimakariri to the Canterbury settlers south of Leithfield, it would be preferable to arrange with the Nelson Government for bridging the Hurunai at the joint expense of the two provinces, and connecting the Nelson track with the Teramakau valley by catting a branch line from the Pakihi to the Ahaura. These works would be a material benefit to both provinces, whilst on the completion of the Nelson road Canterbury would reap the advantage of having a route to the West Coast from the north of the province without taxing its revenues for the cost of its construction.

I have prepared and annexed to this report a map showing the position and heights of the passes between the Waimakariri and Teramakau, with eeetions of the principal passes and of the valleys of the Waimakariri and Teramakau, all drawn to a uniform horizontal scale of one inch to the mile, and to a uniform vertical scale of five hundred feet to the inch. A comparison or these sections will convey a great deal of information respecting the dividing range which could hardly be learnt from a verbal description. I have also forwarded (appendix C) a copy of my journal containing various details respecting the alpine district in which I have been travelling, which could not have been introduced into the body of this report without adding unnecessarily to its length. In conclusion I must express my obligations to Mr. Hawden and Messrs. Goldney Brothers, whose hospitality and assistance materially forwarded the work of the survey, and enabled mc to complete my examination of the passes much sooner than I could otherwise have done.

I have the honor to remain, sir, Your obedient servant, (Signed) E. DoBSOH, Engineer of Lyttelton and Ghristchurch. Railway. The Secretary for Public Works.