Shingle on the East Coasts of New Zealand, 53 



is the chief subject of this paper ; but the action of the waves 

 on sand cannot be wholly neglected, as the difference is 

 chiefly one of degree. 



I. — Description of the two Beaches Visited. 



3. The author visited what is known as the Ninety-mile 

 Beach, on the east coast of the South, or, as it used to be 

 called, the Middle, Island, and the beach near Napier, in 

 Hawke's Bay, on the east coast of the North Island. 



4. The Ninety-mile Beach extends from Banks' Peninsula 

 in a south-west direction to Tiroaru, but the same beach 

 really extends some 50 miles further down the coast in a 

 southerly direction to Oamaru. There is an uninterrupted 

 shingle beach over 130 miles in length. The principal 

 source of supply of this shingle is the River Waitaki, or, as 

 it is called on the Admiralty chart, the Waitangi, which 

 is about 14 miles north of Oamaru. " Cliffs from 30 to 

 40 feet high" are marked on each side of the mouth of this 

 river. Some of the shingle is said to come from these cliffs. 

 The shingle on the beach opposite Oamaru is evidently 

 driven there when the wind is north of east. South- 

 easterly weather would formerly tend to denude the beach, 

 but since a breakwater has been constructed at that place 

 shingle has been collecting opposite the town. It is said 

 that the accumulation near the mole on the north side of the 

 new harbour has ceased ; but this may be only temporary. 

 The same agency which caused the present accumulation is 

 still at work. North-easterly weather must continue to 

 drive shingle down the coast from the River Waitaki, and 

 unless the mole causes the shingle to be deposited at a point 

 sufficiently distant to allow of its being carried back during 

 south-easterly weather the accumulation must go on, though 

 it may be but slowly. 



5. South-easterly weather prevails on this coast, and as 

 the beach between Oamaru and the River Waitaki is supplied 

 chiefly from that river, which is to the northward, this beach 

 is probably at times denuded, the cliffs being then cut 

 away. The beach between the river and Timaru is probably 

 less subject to change, owing to the chief supply of shingle 

 being at the end from which the prevailing seas come. 



6. South-west of Timaru, at the end of the town, is 

 Patiti Point, where there is a low cliff with a shingle beach 



n front. It is at first difficult to account for the beach 



