MuLGAN, — The NonJiern Wairoa. 461 



west. Seen from the south it presents a broad surface hke 

 that of a wall viewed at right angles to its length ; from the 

 north-east or south-west it has the appearance of a wedge, 

 bi'oad below and tapering above. About two miles south of 

 Maungaraho is the Tokatoka Peak, a well-preserved volcanic 

 neck rising through the shales to a height of 580 ft. The base 

 is relatively large, but the summit tapers to a point with an 

 area of a few square yards. In the upper portions well-defined 

 columnar structure is seen ; but this disappears some little dis- 

 tance from the top. The rock can be traced to the river, 

 where it forms a low cone-shaped boss. Between the Peak 

 and the boss — known as Cemetery Hill — is a well-marked 

 depression. None of the rock here presents the appearance of 

 a lava-flow, but rather that of the remains of the upper portion 

 of a subterranean reservoir. To the east the volcanic rocks 

 pass under the shale and reappear again about a quarter of a 

 mile further on. The rock here is much weathered, but lying 

 on and showing through the surface are a number of boulders 

 compact and fresh-looking. They consist of a hard close- 

 grained andesite with large well-defined augite crvstals. A 

 short distance further on the junction of the shale and volcanic 

 rock can be seen in an old road-cutting. At this point the 

 rock is much decomposed, but the remains of the augite cry- 

 stals can be plainly seen. About a mile to the south of the 

 Peak the same rocks again outcrop in a low rounded hill, 

 which is evidently a boss. The rocks here cross the river in 

 a south-west direction, reappearing in a well-defined conical 

 hill rising through the river-deposit, known as the " Green 

 Hill," and consisting of a hard-grained andesite very similar to 

 the boulders found to the east of the Peak. Much of the rock 

 at this exposure shows but httle sign of decomposition, and will 

 in the future furnish valuable material for road-metal. A 

 httle more than a mile to the south of this spot another similar 

 outcrop occurs, bare at low tide and a source of much danger 

 to vessels. In the Tokatoka Swamp itself, about a mile and a 

 half back from the landing at Eaupo, these rocks agan:i rise to 

 the surface, where quarrying operations are carried on. The 

 rock is broken in a steam-crusher and used for ballasting the 

 railway-line running through the swamp, as well as for spread- 

 ing on the roads. There is little or no doubt that these out- 

 crops are connected, and have had their origin in some com- 

 mon reservoir. 



The land between the Wairoa Eiver and the coast con- 

 sists for the most part of soft sandstone arranged in horizontal 

 layers, which under the action of the weather crumble into 

 white sand composed in places almost entirely of silica. At 

 the coast the rocks are very soft, and are readily acted on by 

 the atmospheric agents of erosion. Great quantities of the 



