108 Transactions. 



be doubted that they occur. Disconformities, or planes representing periods 

 of standstill and non-deposition, are also known — e.g., that between the 

 Weka Pass stone and Amuri limestone, and that between the Hutchinson 

 Quarry beds and Ototara liinestone. The probability of a palaeontological 

 disconformity between the Greta beds and the Mount Brown beds has been 

 discussed above. Important differential earth-movements were certainly 

 operative in the production of the great Marlborough conglomerate. There 

 is more than one limestone in North Canterbury and in North Auckland — 

 e.g., in the Waipara there are the Amur-i limestone, the Weka Pass stone, 

 and the Mount Brown limestones. The main limestones are of different ages 

 in various localities, and there are at least three distinct calcareous horizons 

 in the younger rocks — viz., those of the Amuri limestone, the Ototara lime- 

 stone, and the Wairarapa limestone — with possibly a fourth in the Takaka 

 limestone, each of these rocks representing in their respective localities the 

 period of maximum submergence. The claims made by Marshall for his 

 Oamaru system are not justified on the facts. 



Marshall has not elaborated the possibilities of simple overlap, combined 

 with subsequent (Kaikoura) differential movements, in explanation of the 

 localization of various beds, and it will be instructive to do so. I am 

 indebted to Dr. J. Henderson for this suggestion. According to this hypo- 

 thesis, if the sea-bottom seaward of the Oamaru district were to be uplifted^ 

 and dissected it would reveal in the seaward part a sequence like that of the 

 Clarence Valley, followed inland by one like that of the Waipara, with 

 finally the Oamaruian sequence farthest inland. The Oamaru district differs 

 from the Waipara and Weka Pass district, and that in turn- from the Clarence 

 Valley, in that it has not been so much uplifted by the Kaikoura movements. 

 The Waipara district should be succeeded inland by an area similar to the 

 Oamaru district, if erosion has not destroyed it. This is probably the case, 

 for the Piripauan and the Amuri limestone are unknown on the Culverden 

 side of the Hurmiui-Waiau depression where Oamaruian beds are found. 

 As the sea commenced to withdraw again after the maximum overlap in 

 the Oamaruian, the lower Wanganuian beds should not be found so far 

 inland as the Oamaruian ; and this too is the case, for the Greta beds are not,, 

 so far as I know, found inland of the Amuri limestone. Similarly, in,- east 

 Marlborough, the Clarence and Awatere Valleys with their Clarentian beds 

 should be followed inland by an area like the Waipara with Senonian beds 

 and Amuri limestone, and this in turn by an area like Oamaru. The latter 

 may be represented by the Picton area, but the Senonian intermediate area 

 is missing. Towards the upper Clarence any such beds might have been 

 destroyed by uplift and erosion, but in the upper Wairau they slioidd surely 

 have been preserved. Again, the Clarence Valley area should preserve not 

 only the lower Wanganuian as well as the Oamaruian, but also the upper 

 Wanganuian, which is not the case. - 



The arrangement of the three provinces along the coast-line, with the- 

 Waipara type between the Oamaru and Clarence Valley types, is again in 

 accord with the hypothesis ; but this demands a progressively greater eleva- 

 tion of the two northern areas either by warping or by block-faulting. This 

 is found in east Marlborough, but there is little evidence of it in North 

 Canterbury. 



It will thus be seen that this hypothesis that simple overlap' with sub- 

 sequent differential elevation is the cause of the present localization of the 

 various types of stratigraphical sequence is in accord with many of the facts, 

 but by itself cannot satisfactorily explain them all. It does not explain, 

 for instance, why the lower Wanganuian beds are confined within the 



