412 Transactions. — Geology. 



J. von Haast mentions one of these in a report on the water- 

 supply of Timaru. A much larger patch was cut into in 

 " stripping" off the clay at the North Mole Quarry, on the 

 bank of the Wai-iti Creek. This patch rises upwards from 

 the creek as though laid down upon a sloping bank ; the bank 

 of clay it overlies is well veined and worm-bored. During 

 the formation of a mass such as this from wind-borne dust, it 

 could not but happen that now and then storm-waters would 

 scour away from one place, and deposit in stratified form in 

 another, some of the surface-soil. These rearrangements of 

 material would naturally be made most frequently near the 

 large watercourses, and it is in such positions that the only 

 two cases I am aware of are found. The one mentioned by Sir 

 J. von Haast is in the cliff bounding the Waimataitai Valley, 

 on the south side. It consists of a small patch, as seen in 

 section in the sea-cliff, 10ft. or 12ft. wide, 4ft. or 5ft. deep, 

 and situated about midway up the cliff. The other case, as 

 already stated, is beside the Wai-iti Creek. Granting that 

 this bedded layer was laid down by a flood in the creek, it 

 must appear that the stream had not then cut through the 

 50ft. of dolerite rock as it has done, and through some 150ft. 

 of the underlying drift-formation besides. The Waimataitai 

 Creek has similarly, but in less degree, cut down its channel 

 «iuce the patch of stratified loess was laid down." 



In dealing with the vestiges of vegetation mention was 

 made of a fine, somewhat plastic clay which occurs here and 

 there, and regarding which it was suggested that it must be a 

 mud deposited by pools of storm-water. This view is sug- 

 gested by the fact that the best specimens of it are found in 

 hollows in the rock-surface. In the North Mole Quarry a 

 depression in the rock- surface was evidently almost filled by 

 it, the deposit exceeding 2ft. in depth in the centre, and thin- 

 ning out towards the margin of the hollow. In many places 

 the mud-bed is formed, not at the base, but at some higher 

 and apparently not constant level, yet never far from the 

 base. A hint is supplied by the case of Wai-iti Creek, and the 

 stratified silt at Waimataitai (which rests upon a similar mud), 

 that the cutting-down of the channels after a time prevented 

 the overflowing of storm-waters, and the production of more 

 mud-beds and bedded rearrangements of the silt. 



Summary of Evidence. — I think it will be conceded that 

 the evidence herein adduced is sufficient to prove the growth 

 of the Timaru loess as a strictly dry-land — an ^olian — deposit. 

 There are good evidences of several old land - surfaces in 



' Since this paper was written it has occnrred to me that the Wai- 

 iti Creek patch was more probably a wind-clrift. Unfortunately this idea 

 did not occur to me soon enough, for on going to the quarry to re-examine 

 it I found it had been nearly all carted away. 



