Marshall and Murdoch. — Tertiary Eocks near Wanganui. 117 



(3.) Nukumaru Beach. — This locality is six miles to the north of Kai 

 Iwi, and extends over a distance of one mile to the south of the boat- 

 landing. The strata here are of a much coarser grain and are highly 

 micaceous. In some of the strata there are pebbly bands. The pebbles 

 are formed of extremely hard submetamorphic sandstones, or greywackes, 

 often penetrated by quartz veins. Many of them are of a green tint. 

 Much of the fossiliferous material in this locality is of a concretionary nature. 



(4.) Waipipi Beach. — This is nine miles north of Nukumaru. The 

 strata here consist of a stiff and fine blue clay, with occasional bands 

 of fine micaceous sandy matter. It is mainly in these bands that the 

 fossils are found. The best localities are directly north of the mouth of 

 the Waipipi Stream and on a projecting headland three-quarters of a mile 

 farther to the north. Sometimes as the sand drifts with changing winds 

 and tides very fine fossils are exposed above low-tide level between these 

 two localities. 



It may be said definitely that lithologically the strata are of the same 

 general nature throughout. A bluish-grey fine-grained sediment is the 

 ordinary material. This in places becomes sandy, especially between 

 Kai Iwi and Nukumaru, where there is much false bedding, due appa- 

 rently to rough-weather and tidal scouring, for there does not appear to 

 be any actual beach formation. Sometimes the fossiliferous bands have 

 an extremely marked concretionary nature, and then the rock becomes a 

 hard arenaceous limestone ; but this is always a shoal-water rock, and it 

 generally contains a number of small pebbles. This is the nature of the 

 Nukumaru limestone, which is really a shell conglomerate. This hard 

 rock fronts the coast for a distance of some three miles north of Nukumaru 

 Beach. 



The strata always strike to the east of north. The most northerly 

 strike is N. 27° E., at the mouth of the Waipipi Stream, and the most 

 easterly N. 85° E., near the mouth of the Kai Iwi Stream. The average 

 throughout the whole distance is considered to be N. 70° E. The dip is 

 always to the south-east, and its amount is small throughout — never more 

 than 6° and never less than 2|°. The average is considered to be a little 

 over 4°. 



No dislocations of any importance have been seen in the strata, though 

 the sea-cliffs, which are continuous from Castlecliff to three miles north 

 of Nukumaru, have been closely inspected throughout the whole distance. 

 There are some small faults, but they always have a slight throw only. 

 Nothing of the nature of an important unconformity can be seen. Three 

 miles to the north of Kai Iwi an old land-surface can be seen distinctly 

 in the stratification. The evidence of this is found in a stratum of beach- 

 worn pebbles, a carbonaceous stratum with roots penetrating the blue 

 clay beneath, and a number of molluscan bores penetrating it. There is, 

 however, no discordance in the stratification, and no species of moUusca 

 were found in the strata lying just above the old land-surface different 

 from those that were found beneath it. It is, however, noticeable that 

 Crepidida gregaria was far more abundant in the rocks below than in 

 those above this old surface. The structure is certainly due to a purely 

 temporary emergence of what was probably a small portion of the area 

 of deposition. 



There is another instance of interbedded carbonaceous matter and 

 of penetrating roots near the south end of the Nukumaru Beach, a 

 quarter of a mile to the south of the place where the fossil moa-bones were 

 found. This is a far less marked instance than the former one. These 



