26 
The N.Z. Journal of Science and Technology. 
[Mar. 
the hills. The graded slope of the flat is continued along this valley, and 
terminates in a marine shelf cut in soft rock and veneered with beach 
gravels and sand. This bench, 80 ft. to 90 ft. high, is prominent north 
and south of the mouth of the Jed. Evidently the Cheviot flats were 
formed during a period of standstill when the land was about 90 ft. lower 
than at present. The extensive terraces, 80 ft. to 120 ft. above present 
river-level, that occur in the depression south of the Waiau-uha and north 
of the Hurunui were formed during the same period, as also was the valley- 
floor that may be traced for some distance along Buxton Creek, a small 
stream entering the sea half a mile south of the Jed. A raised beach about 
a dozen feet above sea-level extends more or less continuously along the 
shore south from Buxton Creek to Gore Bay. While this beach was 
forming, the streams were cutting back up-stream and entrenching them¬ 
selves in their 90 ft. valley-floors, a process that is still continuing. Jed 
Stream is entrenched for about a mile only from its mouth, but the Waiau- 
uha and Hurunui have cut back beyond the Cheviot depression. Their 
branches, which are now deeply entrenched in the soft rocks of the lowlands, 
have captured streams that at one time discharged into the Jed. Thus 
Swamp Creek now flows to the Waiau-uha through the low hills north of 
the Cheviot flats, and the two small streams that formerly entered the 
south-western corner of the flats at Ho Noti have been diverted to the 
Hurunui. At Port Robinson a raised beach from 220 ft. to 250 ft. above 
sea-level is prominent, and remnants of yet higher beaches occur a little 
north of this locality. 
General Geology. 
The oldest rocks of the district are siliceous and unfossiliferous grey- 
wackes and argillites. McKay reports that a 40 ft. band of conglomerate 
containing pebbles of rhyolite, granite, quartz, &c.,* occurs on the east 
slope of the Cheviot Hills. The strata as a whole have been intensely 
folded, and later much crushed and faulted. 
About a mile up-stream from the mouth of the Jed the unconformable 
contact of the greywackes and the overlying beds was examined. The 
nearly flat surface of the older rocks was probably produced by marine 
planation. The basal layer of the younger strata is a conglomerate 10 ft. 
to 12 ft. thick, containing large rounded and subangular boulders of grey- 
wacke in a matrix of glauconitic mudstone. Overlying are beds of shale, 
mudstone, argillaceous sandstone, and greensand, as well as the various 
intergradations. These beds, which strike east-north-east and dip south¬ 
ward at about 20°, may be 50 ft. to 70 ft. thick. They are overlain by 
porous bluish-coloured sandstone, from which the rocks in the bed of Jed 
Stream known as “ The Brothers ” have been carved. Glauconitic sandy 
beds overlie, followed by a blue argillaceous sandstone 120 ft. thick which 
contains lenses of coarse sandstone, limestone, and sandy limestone, and 
which passes upward into a 20 ft. bed of white chalky limestone. In 
Speight and Wild's paper of 1918 this limestone is correlated with the 
Amuri limestone, apparently on the unsafe ground of lithological 
resemblance. 
From the lower glauconitic beds exposed along Jed Stream, Haast, 
in 1870, collected saurian bones. These rocks again outcrop near the coast 
* W. J. Sollas and A. McKay, The Rocks of the Cape Colville Peninsula, vol. 2, 
pp. 160-73, 1906. 
