Otumoana Pa

This ridge fort is situated near the Urenui river, on the left bank, about a mile from the main road bridge. This is not an isolated ridge-like hill, as is Urenui pa, or the fortified extremity of a flat plateaux, as are Kumara-kaiamu and Te Kawa, but the summit of a narrow ridge has been levelled into seven main areas at different levels, and extending for a considerable distance. The fortified part of the ridge is connected with the plateau to the S.W. by a narrow neck that is lower than the defended area. This low and narrow part was selected by the neolithic engineers as the most desirable place for the outermost defence. See Fig. 62, p. 227.

Referring to the plan of Otumoana, the letter A marks the very narrow part of the spur, from which point the ridge summit rises gradually until it reaches its highest part at the south end of O area. The scheme of defence was the levelling of the ridge top into areas of various heights and sizes, each area being separately defended by fosses, scarps, parapets and stockades, so that each area was in fact a fort in itself. Thus there were seven fortified posts, each of which could be defended as a self-contained area, and not including the lateral terraces which were residential areas, the outer limits of which would be defended by stockades and scarped faces. The strongly fortified divisions were those marked, P Y, X, Z, K, M, and O. Below these summit areas terraces have been formed for residential purposes on both sides of the ridge. Those on what we may term the northern side have suffered much from erosion and other destructive agencies, and are not now continuous or even traceable throughout. On the southern side the terraces are much better preserved, having been protected by a fine growth of light bush composed of mapau, kohe, karaka, tawhero, mahoe, rewarewa, rnamaku, etc., which trees flourish in a light and kindly soil.

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Proceeding onward from A where the ridge summit is very narrow, we find the first sign of defensive work at B, where a short fosse 5 yds. long and 7 ft. wide has been carried half way across the ridge summit. The inner end of this trench now shows a scarp of 7 ft. Presumably the entrance was situated at the southern end of the fosse, the small area between it and the scarp at C being enclosed by palisading. An enemy forcing an entrance through this gateway would be immediately confronted by the scarp defence at C, which is now 6 ft. in height and would be surmounted by a stockade as an additional barrier.

Rising to the area marked P we find it to be a levelled space of somewhat triangular form, 6 yds. wide at C and increasing to 16 yds. at the other end, the trend of the ridge top being about S. W. to N.E. In length this P area is 23 yds. This is the first of the artificially levelled self-contained defensive areas. Its defence on the C line is given above; that at the opposite end of the area was a deep wide fosse, while the lateral defences, now showing merely steep slopes, were undoubtedly scarped faces when the place was occupied. All these scarps, as also those of the various fosses, would be surmounted by stockades consisting of stout posts with horizontal rails lashed thereto, to which the strong palisades would be secured. It will be seen that the defences of this fort are of the type usually employed by the Maori in the construction of ridge forts, viz., fosses, parapets and stockades, with steeply scarped slopes, across the ridge as frontal defences; while the lateral defences along the sides of the ridge consisted almost entirely of steep scarps surmounted by stockades. All signs of the latter have, of course, long disappeared. We shall see that a curious usage, already noted in the descriptions of other forts, is also in evidence here in the lateral or flank defences, namely the singular change made where a flat terrace is transformed into a fosse with an outer parapet or wall. Presumably it was considered advisable to strengthen the defences at such places. These flank defences were not so liable to be taken as frontal ones simply because no vantage point for attack could be found outside them, the ground falling more or less steeply from the base of the high scarps.

The fosse D, E has assuredly been a very strong defence. It is 20 yds. in length, extending right across the ridge top. Its scarps are extremely steep, that on the inner side being practically vertical, save at its base, where lies a mass of detritus; it is nevertheless still 16 ft. high in the middle, a formidable defence if surmounted by a 10 ft. stockade. The outer scarp, on the P area side, is 12 ft. high in the middle. At 4 ft. from the bottom of the fosse its width is 14 ft. The brow to brow measurement is about 18 ft., the brows being page 229somewhat eroded and the bottom of the fosse rounded by the effects of such erosion. The lower part of the trench has been hewn out of soft sandstone.

Area Y lies 5 ft. higher than area P but is much smaller, being but 7 yds. by 19 yds. These terrace-like areas were of various dimensions according to the slope and contour of the ridge top, hence the discrepancy in size. Some would accommodate a large number of huts, others very few, the residential sites being, however, largely increased by the subsidiary lateral terraces formed on the hill sides below the summit areas.

The F, G fosse is 18 yds. in length, the S.E. end being 5 ft. lower than the other. It is 15 ft. wide above the debris-rounded bottom and has probably been that width at the bottom originally. The outer or western scarp of the fosse is from 6 ft. to 10 ft. high. The inner scarp is now about 18 ft. high, to which must be added the depth of debris in the trench, showing that this defence must have been an imposing one; indeed at its S.E. end this fosse shows a 20 ft. scarp on its inner side. Brow to brow is about 25 ft. The hillside to the S. is still steep, but on the other side a terrace has been formed. It is of interest to note how some of these lateral terraces run into the fosses and into each other. A double and occasionally treble system of terraces has existed on this northern side of the ridge, but these terraces are much broken away in places, hence their original arrangement cannot be fully delineated.

The next area, that marked X, presents a different form, inasmuch as from its two wings extend terraces along both sides of the ridge. On the south side, at H, which is 38 yds. from F a secondary terrace starts at a lower level, while the terrace on the other side is joined by that running from the Y area, and continues as far as the J ditch, where it ceases abruptly, while the remains of two other terraces are noted below it. The southern side of the X area is very steep and has a fine growth of light bush. This area is well levelled and quite flat. The terrace round the southern (S.E.) side of Z area is 18 ft. wide. That on the northern side is 20 ft. in width and extends 65 yds., its inner scarp being 11 ft. to 14 ft. in height.

Ascending an 11 ft. scarp from X area we attain another levelled space marked Z on the plan. This terrace is 43 yds, long and 23 yds. wide at its eastern (N.E.) end. Below the southern face of this area the terrace from X area resolves itself into a trench or fosse with an outer parapet, with an inner scarp of 8 ft. to 11 ft. and outer scarp of 3 ft. The trench is much filled with detrital matter. The parapet or outer wall widens out as it advances and near its termination is 18 ft. wide and of a flat-topped formation. It probably represents part of page 230the original formation reduced by levelling operations, and not a true construction. The lower terrace from H lies 7 ft. below this flattened wall. At the inner or eastern end of Z area, extending along the eastern brow of J, J fosse are the remains of a parapet or superimposed wall now from 3 ft. to 5 ft. high. Also are seen slight signs of the former existence of such a parapet along the southern brow of this fosse. There was probably a gateway or passage at the southern end of the fosse, as marked. This may have been the site of a removable bridge across the fosse to give access to K area from Z, or it may have been an entrance to Z area from the lower lateral terrace by way of the fosse.

This J, J fosse is 25 yds. in length and debouches on to terrace formations at both ends. Its eastern or S.E. scarp is 11 ft. in height, and the opposite one is 6 ft.; scarps considerably eroded. Brow to brow about 18 ft. Width 12 ft. The western end of K area is somewhat lower than Z area.

The western end of K area is about 7 yds. wider than the eastern end of Z, and projects out on the northern side. This is owing to the discontinuance of the lateral terrace on that side, which here ends abruptly. K area is 74 yds. long, 19 yds. wide at its eastern end and 31 yds. at the western end. Its expanse has been carefully levelled for residence and the ridge top here is somewhat curved. On the southern face the lower terraces run out, the ground showing a gentle slope for 50 ft. which space was probably utilised, after which it drops steeply. Towards L the southern slope drops steeply from the summit. There seems to have been an entrance, as shown on plan, from this southern side. The northern side shows a steep slope for about 100 ft. and then a more gradual descent to the flat below. The central part of this sideling shows no signs of terracing, but much eroded remnants of terraces are seen near the ends of the area.

The fosse at L is 18 yds. long and 8 ft. wide, but unusually shallow, in fact it may be termed a mere shallow trench. Its western side presents a scarp of but 2½ ft. though the inner scarp is from 8 ft. to 12 ft. which must have been the principal defence here. There was apparently an entrance way here from area K to M, as marked. The superior height of the eastern scarp of the trench is produced by a parapet or superimposed wall of 5 ft. on that side.

Area M is 5 ft. higher than K, is level, and measures 30 yds. by 23 yds. Its eastern end shows the remains of a parapet on the brow of the fosse now 3 ft. to 6 ft. high, with signs of a passage in the middle thereof. The N, R ditch is 33 yds. long; it extends some way down the southern slope outside the line of defence. It is 10ft. wide at the bottom and 12 ft. to 15 ft. at the top; the scarp on the page 231eastern side 6 ft. to 12 ft. high, that on the western side 11 ft. to 12 ft. In all these measurements decay must be taken into account, the erosion of scarps and parapets, as also the collection of detritus in fosses and at scarp bases. Below the northern side of M area is a terrace.

Area O is the last and largest of the series, the ridge top widening out at this place, after which it contracts at the U, T line and descends as a narrow spur to the river flat. Its western end shows an earthen parapet now 4 ft. to 5 ft. high on the eastern side of the N, R fosse, also the remains of a similar parapet for 40 yds. along the R.S line. This area is 130 yds. long and its western end marks the highest part of Otumoana pa. It has been levelled in areas for occupation but has a slight fall to the N.E. Though only 30 yds. wide at S, it widens out considerably from that point. At V the ridge narrows suddenly and falls away on its descent, hence this spot has been selected by the fortification experts as the limit of the fortified area. A deep fosse 40 ft. long has been cut across this narrow part of the spur, and this still presents an 18 ft. scarp on its inner or western side, the outer scarp of the ditch being 8 ft. high. This is the outermost defence, and the inner scarp of the fosse was probably not less than 25 ft. in height when the pa was occupied. This imposing defence does not represent the original height of the ridge at this part, for it is clear that the parapet marked on the plan is a built wall superimposed on the northern half of the crest of the original scarp extending from U to T. This parapet is still 5 ft. high in places; the original surface is plainly seen on the scarp batter.

The southern part of the T, U defence is a plain scarp clear of the fosse, and 16 ft. below which is a much eroded terrace. Here we lose the bush on the southern face of the ridge, the whole northern face being clear. The scarp along the southern side of O area is now 6 ft. to 12 ft. high, below which a terrace extends for some distance.

Proceeding from T to W we find a scarp 16 ft. to 11 ft. in height, at the base of which is a fosse 9 ft. wide and outer rampart 3 ft. to 5 ft. high. Further on the width of the fosse increases to 10 ft. as the scarp decreases in height. Below, the sideling falls steeply away to the flat far beneath. Some parts of the scarped face are still extremely steep. The outer rampart is lost as we proceed, and the fosse becomes a terrace, to again assume the fosse and parapet form on approaching S, while below it is a short terrace 60 ft. in length. From S onward to R no lateral terrace formation is noted. At R commences a shattered terrace about 12 ft. in width, the inner scarp of which is some 15 ft. in height. This terrace ends page 232abruptly at the next fosse, whence we follow a steep face, broken some 60 ft. below the summit by small terraces, probably hut sites with no defences. Approaching J the upper terrace is again encountered, which becomes a secondary terrace under Z area, where it divides into two, the upper one running under X area into the F, G fosse, with a rampart 6 ft. to 10 ft. wide along its outer edge, the lower one extending to fosse D, E. These terrace formations show scarps up to 20 ft. in height, but are much eroded.

With regard to the earthen parapet on the brow extending westward from S to the N, R fosse, this was probably an extra defensive item to compensate for the lack of any outer defence. The Maori engineer had several methods of strengthening weak parts of a line of defence.

A remarkable feature in this old fort is the fine condition of the larger fosses, of which some of the scarps or walls are almost vertical. Indeed this is the most interesting of the many forts examined in this district.

Local bushmen state that, in the forest country between Urenui and the Whanganui river are many apparently very old forts, all small and forest covered, with trees of considerable size growing in the works. In these places are many store pits excavated at the bases of the trench scarps.

Trees mentioned above:—

Mapau = Myrsine Urvillei
Kohe = Dysoxylum spectabile
Karaka = Corynocarpus laevigatus
Tawhero = Weinmannia sp.
Mahoe = Melicytus ramiflorus
Rewarewa = Knightia excelsa
Mamaku = Cyathea medullaris.