486 EEPOKT— 1891. 



sixteen miles to the north of Hokitika. The bodies of persons 

 drowned in the Grey and Buller are always found on the beach 

 to the north. I have noticed the characteristic red-granite 

 shingle of the Buller Eiver on the beach near Mokihinui, 

 twenty-five miles to the north. The slate and granite shingle 

 of the Grey Eiver is found on the beach many miles beyond 

 Point Elizabeth, where neither the rocks nor the creeks con- 

 tain this kind of stone. A ship with coals was wrecked at 

 Napier, and very soon afterwards fragments of coal were 

 found by the late Mr. Webber at Mahia, nearly seventy miles 

 to the north. At Timaru, bricks thrown into the sea were 

 observed to travel north at the rate of a mile a day. At Grey- 

 mouth, limestone rocks washed out of the south breakwater 

 into the river were swept by the flood out to sea, but soon ap- 

 peared on the north beach, travelling north. At Timaru I 

 found basalt stones which had been deposited to protect the 

 railway drifted along the beach three miles to the north. 



There are two methods by which the waves convey material 

 along the beach : First, the oblique waves wash shingle and 

 sand obliquely up the beach, and the recoil draws it down at 

 right angles. This method is made use of to convey boulders, 

 gravel, and heavy sand. The second method has a greater 

 effect, which consists in the surf stirring up the sand of the 

 bottom, which is then transported by the currents. 



The waves continually sift the sand from the shingle, and 

 keep the shingle exposed to the grinding action of the waves, 

 for it is observed that the heavier material is driven up to low- 

 water mark, while the recoil of each wave draws the finer sand 

 into deep water, where the currents carry it away. 



For instance, when the breakwater was built at Timaru it 

 was at once observed that shingle accumulated on the south 

 side, while the beach to the north was laid bare of its shingle 

 and sand to such an extent that the sea commenced to under- 

 mine the clay cliffs now unprotected, and the coast-line for 

 several miles north suffered considerable alterations. As the 

 breakwater extended, shingle accumulated in an enormous 

 quantity, but did not go round the end of the breakwater : 

 divers, however, reported a strong current round the end, 

 carrying clouds of sand ; and after some years the beach on 

 the north, which had been swept bare, became covered with 

 sand, which has since increased greatly. At Macquarie Har- 

 bour I noticed clouds of sand drifting with a strong current 

 between South Head and Entrance Island, in 70ft. of water ; 

 and on the bar of the same harbour, the water being beautifull)^ 

 clear, I noticed, as every wave passed, the sand at the bottom 

 was suddenly raised and carried seaward by the current in 12ft. 

 of water. We also anchored off the beach some miles north of 

 this harbour, in 3i fathoms of water ; just outside the breakers- 



