298 T ran sact ions. 



and relative positions throughout the whole of North Canterbury and East 

 Marlborough, and it is unthinkalile that they can be, in each of the narrow 

 strips in which they occur, only locally deposited rocks, and that they 

 were not laid down under approximately uniform conditions in relatively 

 clear seas over a wide area. They are involved between the mountains 

 not only in the Middle Clarence Valley, but also in the Awatere Valley to 

 tlie north-west and near the south-eastern base of the Looker-on Eange, 

 and it is probable, therefore, that they were formerly continuous over the 

 intervening areas and that the Kaikoura and Looker-on Ranges did not 

 exist as such at the time of their formation, although islands mav have 

 existed over their sites. This conclusion has been accepted by Hector, 

 McKay, and Cotton. The great Marlborough conglomerate, however, which 

 occurs near the top of the Notocene deposits of this area, has, on the 

 other hand, all the characters of a narrowly localized deposit, and had 

 not probably at any time a wide lateral extension. 



Although the great Marlborough conglomerate is involved equally with 

 all the other Notocene beds in the Kaikoura orogenic movements, the 

 nature of its constituent pebbles and boulders affords proof of considerable 

 differential earth-movements prior to its deposition. It exhibits in the 

 Clarence Valley fairly regular stratification, and appears to be in the main 

 a fluviatile deposit. The majority of the pebbles are derived from the 

 pre-Notocene rocks, and are small and well rounded. In addition, there 

 are larger and often angular boulders, several feet in diameter, of Notocene 

 rocks, including all the beds down to the Clarentian.* It is obvious, there- 

 fore, that in the area from which the materials of the conglomerate were 

 derived the Notocene rocks had been elevated above sea-level and exposed 

 to erosion, and, since the underlying Notocene beds are nowhere less than 

 4,000 ft. thick and reach as much as 12,000 ft., the amount of earth-move- 

 ment must have been considerable. There is, in the Clarence Valley at 

 least, the further peculiar relation that although the conglomerate contains 

 boulders of rocks exactly similar to the underlying Notocene beds, never- 

 theless it is perfectly conformable to the underlying " grey marls," and in 

 the Dee and Mead Gorges at least there are transitional beds. This relation 

 is explained by Cotton (1914) by the assumption that faulting took place, 

 not disturbing the horizontality of the beds now underlying the conglomerate, 

 but differentially elevating a neighbouring area to an extent of perhaps 

 12,000 ft. Since no folding or warping of the Notocene took place, he 

 concludes that the movements must liave been block-faulting, with the 

 restriction that the uplifted block alone moved. These movements may 

 perhaps be looked upon as the early stages of the Kaikoura orogenic move- 

 ments, and must have affected a large part of the Kaikoura Range. Since, 

 however, the conglomerate is involved equally with the other Notocene 

 rocks in the main Kaikoura deformation, it may best be classed as Notocene. 

 This classification is confirmed by the presence above the conglomerate 

 of marine Notocene rocks. 



While it is indubitable that the middle part of the Notocene as 

 locally developed — viz., the Amuri limestone, Weka Pass stone, and " grey 

 marls " — formed a cover to the oldermass which has since been removed 

 by erosion from the higher ground, it is not so certain that the Clarentian 

 beds were everywhere also j^art of the cover. So far as is at present known. 



* Near Kekerangii, immediately outside the area, the great Marlborough conglome- 

 rate contains large masses of Amuri limestone, some 72 ft. in greatest diameter. 



