68 Transactions. 



many places intruded by a network of basic, semi-basic, and acidic dykes. 

 The post-Jurassic (or Rangitatan) diastrophic movement that folded the 

 ranges of the main axial divide was also responsible for the folding and 

 elevation of the Kaikoura chains, and the subsequent intrusion of the 

 igneous magmas. 



McKay (1886, p. 65) has shown that the rocks composing these chains 

 are arranged in two simple synclinal folds, separated by an anticlinal 

 fold, the crest of which runs parallel with the present course of the Clarence 

 Valley.* 



The folding and elevation of the Jurassic and older rocks took place in 

 the pre-Albian stage of the Lower Cretaceous. The denudation of the 

 newly elevated folds of the main divide began immediately, and continued 

 throughout the whole of the Albian, resulting in the base-levelling of the 

 great peneplain elsewhere called Tahora. At this time the Seaward 

 Kaikoura chain existed as an island, or as a long narrow peninsula. 



During the progress of the Albian base -levelling of the mainland, Albian 

 sediments were being deposited in the deep, clear waters of the fiord-like 

 Clarence Sound, that separated the Kaikoura chains. After the post- 

 Jurassic folding, and before the Albian, the crown of the. Clarence anticline 

 was deformed by powerful faults, the most important of which followed 

 the base of the Inland Kaikoura chain. 



The floor ol the Clarence Valley is occupied by a sheet of strata many 

 thousand feet in thickness, ranging in age from Lower Utatur (Albian) to 

 newer Pliocene or even Pleistocene. Two unconformities have been recog- 

 nized in this pile of material. The Lower Utatur strata are followed by 

 the Amuri limestone, which, according to Henry Woods (1917, p. 4), favours 

 the view that the latter is of Tertiary age, since the Upper Utatur (Lower 

 Chalk) beds that normally follow the Lower Utatur in India, Japan, 

 Madagascar, and Zululand are not known to be represented in New Zealand. 

 The second unconformity comes between the Awaterean marine clays and 

 a remarkable deposit which McKay (1886) called the ' post-Miocene 

 conglomerate." 



The Post-Miocene Conglomerate. 



This deposit attains in places a thickness of 600 ft. Tt is mainly 

 composed of water-worn drift, derived from the Juro-Triassic argiUites, 

 greywackes, and associated dyke rocks that compose the Kaikoura chains, 

 mingled with a confused pell-mell of angular slabs and irregular masses of 

 Amuri limestone, " gray marls," and fossiliferous Awatere (older Pliocene) 

 clay-rock, some of the former of enormous size. Patches of this deposit 

 occur near the Marlborough coast, resting on an eroded surface of the Amuri 

 limestone. But its greatest development is in the Clarence Valley, where 

 it lies on the " grey marls," a clayey formation that conformably follows 

 the Amuri limestone. 



McKay in his report on the Cape Campbell district (1876, p. 190) gives 

 a good description of this breccia-conglomerat'\ He says, " These con- 

 glomerates are composed in chief part of well-rounded boulders, but have a 

 large percentage of angular blocks of great size, so that they often present 

 the appearance of old morainic accumulations. A great variety of rocks 



* Thomson (1919, p. 305) expresses the opinion that the strikes observed by him 

 would tend to show that a strike west of north is prevalent in at least some parts of the 

 Kaikoura area; and Cotton (1913. p. 244), arguing from the variability of strikes and 

 dip, considers it probable that the older axes of folding make an angle with the general 

 N.E.-S.W. trend of the chains. In my opinion the meagre evidence produced by these 

 writers is not sufficient to invalidate the considered generalizations of McKay. 



