Thomson. — Geology of Middh Waipara and Weka Pass District. 331 



belonging to the Pareora system (Upper Miocene), but Park suppressed 

 that system throughout New Zealand, and correlated the Motunau beds 

 with the Te Aute or Waitotara series, of older Pliocene age, thus returning 

 to the original correlation of Hector (1869) and von Haast (1871). He 

 described an unconformable contact between the Motunau beds and the 

 underlying Mount Brown beds. 



It is of interest to note that Park also accepted the earlier views of 

 Hector, Hutton, and von Haast as to the pre-Notocene physiography. He 

 considered that the main mountain features of New Zealand were alreadv 

 determined in the Eocene, and that the present intermont basins were old- 

 Tertiary fiords and inland basins which before the Miocene submergence 

 were merely deep valleys of erosion. 



The modern revival of interest in the district commenced with the paper 

 o'n the younger rock-series of New Zealand by Marshall, Speight, and 

 Cotton, in 1911. They restricted themselves to a critical examination of 

 those localities where unconformities had been Reported by earlier observers, 

 and recorded their conviction that there was no unconformity in the Wai- 

 para and Weka Pass'district. A map and block-diagrams of the Weka Pass 

 were given to explain the erroneous view of Park that the Weka Pass stone 

 and Amuri limestone were thrown into folds in which the Tertiaries take no 

 part. The north-western part of the Notocene strip, from which the upper 

 beds had been denuded, was thrown into folds whose pitch did not carry 

 them beneath the south-eastern part, where the Upper Tertiaries are pre- 

 served. The pecTuliar characters of the contact between the Amuri lime- 

 stone and Weka Pass stone are attributed to a change of conditions of 

 deposition. " The change from pure (Amuri) to glauconitic (Weka Pass) 

 limestone does not take place throughout the mass of the rock, but inter- 

 laminations of glauconitic matter arise and separate pieces of limestone. As 

 the conditions that control the depositions become more changed the inter- 

 laminations of glauconitic matter become larger, and the pure limestone is 

 reduced to nodules which appear like rolled pebbles." The contact relied 

 on by Hutton for an unconformity between the " grey marls " and Mount 

 Brown beds was considered a fault-contact within the Mount Brown beds. 

 The section on which Park relied for an unconformity between the Mount 

 Brown and Greta beds was described as showing complete conformity. 

 The authors did not express clearly their views as to the pre-Notocene 

 physiography, but apparently agreed with the view, accepted by all others 

 than McKay, of a diversified surface admitting of considerable overlap 

 within a very short distance. 



A period of coiitroversy between Park and Marshall then ensued as to 

 the conformable or unconformable nature of the Lower Tertiaries and Upper 

 Cretaceous of New Zealand. Park's first reply (1911) did not deal with 

 the internal geology of the Weka Pass and Waipara district, but disputed 

 the correlations made with rocks of the Oamaru district, and reaffirmed 

 unconformity between Cretaceous and Tertiary on palaeontological grounds. 

 Thomson (1912 A and b)' recorded a fresh discovery of Oamaruian fossils in 

 the Weka Pass stone, -and noted an unconformity within the sandy beds 

 between the Weka Pass stone and the lower calcareous horizon of the 

 Mount Brown beds, in a cliff of the Waipara River gorge, just above the 

 junction with Boby's Creek. " It appears, however, to be a purely local 

 accident of bedding. With this exception, there is apparent conformity in 

 section throughout the Waipara district." Marshall in 1912 quoted the 

 fossils from the Weka Pass stone, which Park had admitted as conformable 

 to the Amuri limestone, as proving Park's adhesion to the conformity of 

 the Upper Cretaceous and Lower Tertiary. Park (1912, 1913) inspected 

 the new fossil-locality, accepted the Weka Pass stone as Oamaruian, but 



