Hill. — Demulatlon as a Factor of Geological Time. 675 



similar period when slips were as numerous ? " the replies 

 are emphatic and decisive. Several of the settlers refer to 

 the heavy rainfall that took place on certain days. Thus, 

 Mr. Gray, of Waiohika, Poverty Bay, says, " The rainfall at 

 Waiohika measured over 15'36in. from 6 a.m. on 17th June 

 to 6 a.m. on 19th June, sometimes falling at the rate of 

 0'7in. per hour." Mr. W. H. Smith, of Petane, noticed a 

 similar downpour in December, when Sin. of rain fell in five 

 hours, 5-49in. in ten hours, and G'SOin. in nineteen consecu- 

 tive hours. It is when rains like these take place over a 

 district that denudation becomes so marked and often dis- 

 astrous, as in the case of the Hawke's Bay floods in Decem- 

 ber, 1893 ; and most of the slips along the East Coast appear 

 to have taken place at this period of unusual rainfall. 



The total estimate of slips for an area of 1,158,237 acres 

 is 7,693 acres: this is exclusive of the " slips every where " 

 which are said to have taken place on certain lands where 

 estimates are not given. The estimates given here amount to 

 0-66 per cent, of all the land from which returns have been 

 received. In some districts the slips or breakaways appear 

 to have been unusually large. Thus, Mr. George Ormond, 

 on Te Mahia, facing Hawke's Bay, estimates that 500 acres 

 in a block of 5,000 acres have slipped away. Mr. Wood- 

 bine Johnson, of Maraetaha, Poverty Bay, estimates his 

 slips at 1,500 acres out of a total area of 11,500 acres, or 

 more than 13 per cent, of the whole. But even this estimate 

 is exceeded in the case of Mr. Gray, of Waiohika, who esti- 

 mates that 15 per cent, of his land slipped away in one pro- 

 perty of his containing 2,200 acres, and w^iich was improved 

 grass-land. Open and improved country appears to have suf- 

 fered most and bush country least. I have seen some of the 

 extraordinary results of the slips on Mr. Gray's land at Waio- 

 hika. In one case a whole hill-side, some hundreds of feet in 

 height, broke away, crossed a creek at its foot, filled an adjoin- 

 ing valley, and passed over a public road on the opposite side. 

 The impetus was such that huge boulder-like rocks were 

 lodged on the adjacent hill-side. In a few years all traces 

 of this immense breakaway v/ill have disappeared, and some 

 geologist may even suggest that the perched blocks were 

 lodged on the hill-side by means of glaciers. But glacial 

 action is not needed to account for the transference of such 

 blocks, for the degradation of the land is constant, and is 

 much more influenced by water than ice ; and this was truer 

 in the earlier periods of sedimentation than now. 



The large area which is shown to have broken away within 

 a specified district will enable us to understand some of the 

 effects produced on the earth's surface by a rainfall somewhat 

 in excess of the annual average. But let it be assumed that the 

 abnormal rainfall became the average rainfall over the district, 



