158 



Transactions. 



Out of the thirty-seven species of Mollusca enumerated above, ten are 

 Recent, giving a percentage of 27. 



McKay's collections from the " Kekenodon beds " (Geol. Surv. loc. 

 No. 476) and from the Wharekuri greensands (Geol. Surv. loc. No. 486) 

 contain in all thirty-one definitely determined species. If McKay's col- 

 lections and the list given above are combined the percentage is still 27. 



Corals are abundant in the greensands at this locality. The genera 

 represented are Flabellum and Trochocyathus. Aturia ziczac var. australis 

 Hamilton and Kekenodon onomata Hector were also obtained here by 

 McKay and Hamilton. Pachymagas huttoni Thomson also occurred. These 

 greensands, which are similar to the greensands on the opposite side of the 

 the river, contain in their lower portions small quartz pebbles, well rounded ; 

 and occasional pieces of wood up to 18 in. in length, and completely car- 

 bonized, also occur. The lower part of the beds is very concretionary, and 

 the fossils are difficult to remove. The oxide of iron which forms the con- 

 cretionary masses has been derived from the decomposition of the glauconite. 



At the Wharekuri Bridge greensands again crop out, but the fossils 

 are not abundant. The following forms were recognized : — 



Corbula canalicidata Hutt. 

 '^Crassatellites^obesus (A. Ad.) 

 Cucullaea attennata Hutt. 

 Dentalium mantelli Zitt. 



Dentalium solidum Hutt. 

 *Limopsis aurita (Brocchi) 

 Pecten huttoni (Park) 

 Pblinices huttoni Iher. 



Similar corals to those so abundant in the greensands on the banks of 

 the Waitaki River also occur here. 



McKay (1882a, p. 73) always considered that the greensands (Cretaceo- 

 Tertiary) near the Wharekuri bridge lay unconformably below the 

 " Kekenodon greensands " on the banks of the Waitaki River, but he 

 saw no unconformable junction between these two beds. Hutton (1885, 

 pp. 563-64) and Park (1905, p. 523) have shown clearly that McKay's 

 unconformity had no justification, and was merely a deduction in the 

 light of a pre-conceived theory (Cretaceo-Tertiary theory). The writer is 

 satisfied that the greensands form one series of rocks lying immediately 

 on the quartzose rocks of the coal series. As shown above, the greensands 

 contain pebbles of quartz in their lower portions. 



The coal-rocks crop out at Wharekuri a short distance above the bridge, 

 where they are lying in close contact with the greensands. The line of 

 junction is vertical, and is undoubtedly a faulted one, as Hamilton (1904, 

 p. 465) has shown. This vertical fault strikes N. 20° \W. The coal-rocks 

 dip 26° to the west — that is, towards the mountains — which a short dis- 

 tance away rise abruptly from the bed of the creek. McKay considered 

 that the quartz-grits and sandstones associated with the coal in this 

 locality were of Pareora (Awamoan) age, but in other places in the area, 

 as shown above, they dip beneath the greensands, and are undoubtedly at 

 the base of the series. Beyond the coal-mine on the right bank of the 

 creek the following section is exposed : — 



c> ^ ^ ^^ ^ zTS^ 



o o c> o o />l I lo o a ff o 

 ^ o (? ffi I /o (^ ^ 



f-^ o lo ^ Q e 

 t^ ° ^ I / / c ^ ^ ^ ^ o 0, 



(■' 00 f J / ^ o O 6 DO Oof I I i I I //nr^ 



C^) 



Ccl) 



Cc; 



(<t) 



Fig. 2. — Section, right bank of Wharekuri Creek, (a), (c), (e), gravels and 

 sands; (d), fine micaceous sandy bed; (6) and (/), greenish-grey clay. 



