86 president's address — section c. 



The region wheTe the Notocene deposition was most continuous 

 is that of the Kaikoura Mountains of Marlborough. The structure 

 of this first indicated by the excellent work of McKay (1886-90-92), 

 which has been revised and extended by Cotton (1913, 1914), and 

 by Thomson (1913, 1916, 1918), who has cionsidered especially the 

 stratigraphy. The structure is simple, as shown by Cotton's 

 diagram. Here occur the oldest of the Notocene rocks, which rest 

 on an uneven surface of the " Maitai " rocks. There is a thick- 

 ness of from three thousand to nine thousand fees of sandstone, 

 and mudstone, with locally basal conglomerates or coal measures. 

 They resemble the topset beds of a continental shelf undergoing 

 rapid depression, and near the mouth of a large river. Several layers 

 of basalt occur in these sediments. They are mos^ f oesiaf erous in the 

 upper portion, and Woods (1917) has recognised from here sixteen 

 marine mollusca, including Inoceramus concentricus, Turrdites cir- 

 cumtaeniai iii^ and GaiidrT/ceras sayca. Those, and the other fossils 

 present, indicate that the beds are equivalent in age to the Utatur 

 or Albian beds in India and Europe respectively, and show that the 

 first effects of the Cenomanian transgression extended to New Zea- 

 land. The beds in this stage are termed Clarentian by Thomson 

 (1916). The mudstones are followed by a thick mass of hard, 

 chalky limestone, the Amuri limestone, which has here a thick- 

 ness of twenty-five hundred feet, though it becomes thinner when 

 traced to the northwards, and seems tO' extend tO' Cape Campbell, 

 and is, perhaps, represented in the south-eastern portion of the 

 North Island. The greater part of the investigation of this lime- 

 stone has b^>en, however, in the region of its south-western exten- 

 sion into North Canterbury^ where it continues, but with 

 diminishing thickness, for over fifty miles. 



This last area, the Waipara-Weka Pass district has been 

 long held toi be of the greatest importance, and the long 

 series of studies in this region have recently been sum- 

 marized and extended by Thomson (1920). Before, there- 

 fore, discussing the Amuri limestone of the Kaikoura ranges 

 and elsewhere, it is desirable to describ'S the beds which lie 

 beneath it in Canterbury and the coast of Marlborough. These 

 give evidence of a Senonian transgression, which is much the more 

 exte'nsive of the Cretaceous transgressions flooding also parts of the 

 North Island, and of North Otago. The diastrophic province under 

 consideration commences to the east of the Kaikoura Mourrtains 

 and, passing Amuri Bluff, it extends south-westward into Canter- 

 bury for about a hundred and fifty miles in all. The surface, which 

 was submerged in Senonian times, was still fairly diversified, as 

 shown by the overlap of various beds in the Waipara district 

 (Thomson 1920). The thickness of these deposits varies, being a 

 thousand feet at Amuri Bluff (McKay. 1877) ; two thousand feet 

 in the Trelissick Basin (Speight, 1917), but only from eight 

 hundred down to one hundred and fifty feet in the Waipara district 

 The basal coal measures are generally succeeded by a 



