364 Transactions. 



The constituents of the gravels consist predominatingly of the harder 

 elements of the pre-Notocene of the North Canterbury mountains — viz., 

 greywackes, grits, quartzites, and jaspers ; but there are also pebbles of 

 basalts and lamprophyre-like igneous rocks. No pebbles of the underlying 

 Notocene beds have been observed, nor has any clear unconformity with the 

 Mount Brown beds been detected, but the faunal break is such that one may 

 well be suspected, and it is more than probable that outside the area an 

 overlap of these beds on to the pre-Notocene will be discovered. 



Those bands with a harder cement, mostly calcareous, stand up as 

 cuestas on the back slopes of Mount Brown, the Deans, and the hills near 

 Glenmark, but they are not well exposed in the small creeks draining these 

 slopes, and the best sections are those of the Kowhai River in its main 

 branches, the Waipara River, and the Weka Creek. An intermittent section 

 is also yielded b}- the railway-cuttings between V/aipara and the Weka Pass. 



Kowhai River and Mount Brown. — Only a part of the north branch of 

 the Kowhai River was explored, and a discontinuous section of the Motunau 

 beds observed in the creeks draining from Mount Brown. In a cliff facing- 

 Mount Brown, the base of which is about 200 ft. above the top of the main 

 limestone (D), there is an oyster-conglomerate about 50 ft. thick, yielding 

 Ostrea arenicola, succeeded by 50 ft. of hard calcareous conglomerate, and 

 resting on sands with a bed of fragile shell's. 



In a tributary notching the cuesta of the Mount Brown beds, west of 

 Mount Brown, lower beds are exposed. Above the main limestone (D), with 

 Magadina browni, there is a gap of about 20 ft. in the succession, and then 

 there is a further 10 ft. of brown calcareous polyzoan sandstone with much 

 quartz, perhaps still in the Mount Brown series. This is followed by 

 brownisli-green sands and 1 ft. of calcareous sandstone. The succeeding 

 beds are 40 ft. sands, 10 ft. fine conglomerate with pebbles of jaspers, grey- 

 wackes, and dark porphyritic rocks, 50 ft. brown sands, and 10 ft. fine con- 

 glomerate oyster-beds with 8 in. boulders of a white calcareous sandstone 

 containing friable fossils at the base, the same horizon being represented 

 TOO yards down-stream by four separate oyster-beds separated by sands. 

 After a gap of 50 ft. some 15 ft. of coarse conglomerate is exposed. The 

 oyster-beds yielded Anomia huttoni, Ostrea arujasi, and 0. nelsoniana. 



On the road from Onepunga to the Kowhai Valley the first beds exposed 

 are oyster-beds and hard Coarse conglomerates, lying about 200 ft. above the 

 main Mount Brown limestone (D). In the first large cliff in the north 

 branch of the Kowhai River below there are fine conglomerates and sands, 

 with many oyster-beds. The next prominent bed upwards in the sequence 

 is again an oyster-conglomerate with a hard white calcareous cement. 

 About a Cj[uarter of a mile down-stream the first mudstone is exposed, and 

 is a very green rock without fossils. It lies about 300 ft. above the main 

 Mount Brown limestone (D). 



The upper part of the Greta beds is exposed in the lower part of the 

 north branch of the Kowhai River and its numerous tributaries. The 

 rocks are fine conglomerates, gravelly shell-beds, oyster-beds, sandstones 

 and loose sands, blue mudstones and sandy mudstones, and thin lignite- 

 seams. Continuous exposures are not found, and, judging from neighbouring- 

 cliffs, the conglomerates and sandstones are lenticular and not persistent. 

 Fossils are fairly abundant, but are in many cases very fragile. The oysters 

 belong to the species Ostrea angasiy 0. arenicola, and 0. corrugata. An 

 exhaustive collection of the other species was not made, but the following 

 H-ere noted : Chione meridionalis, Gari Uneolata, Modiolus australis, Proto- 

 cardia -pulchella, and SigajMtella novae-zelandiae. , 



