Park. — Marine Tertiaries of Otago and Canterbury. 501 



the old Cretaceous shore-line, like the Oamaru series at a later 

 date. Moreover, it occurs in the Trelissic basin and in the 

 Clarence and Awatere Valleys, which must therefore have 

 existed as arms of the sea prior to its deposition. 



Basement Eocks. 

 In the Waipara district, and in several parts of Marl- 

 borough, and in the country between Onekakara, near Hamp- 

 den, and the Upper Kakanui, the Oamaru series rests on the 

 Waipara formation ; elsewhere it lies directly on the older 

 Mesozoic or Palaeozoic basement rocks. Thus in the Province 

 of Otago it rests principally upon mica-schist and altered 

 sedimentaries ; in Canterbury, upon Lower Mesozoic clay- 

 stones and sandstones ; and in Nelson and Westland, mainly 

 upon schists, quartzites, slates, and other altered sedimentary 

 rocks. 



Influence of Basement Bocks. 



In the places where the Oamaru series rests upon the 

 older basement rocks its lowest member consists of grits 

 and conglomerates, derived from the erosion of the adjacent 

 country. Coal, too, generally occurs with these rocks — at 

 anv rate near the old shore-line ; but in the localities where 

 the series rests upon the members of the Waipara formation 

 the grits, conglomerates, and coal are absent. The absence 

 of the grits and conglomerates is doubtless due to the lack of 

 the requisite hard rock in the Waipara series to supply the 

 materials, but the absence of the coal is the result of causes 

 which are not very obvious. 



Effects of Differential Elevation. 



For the most part, the Oamaru series forms the maritime 

 hills and downs of Otago and Canterbury, and a great part 

 of Marlborough, Nelson, and Westland. It gradually ascends 

 as it proceeds inland, in many places rising to an elevation of 

 between 2.000 ft. and 3,000 ft. in the inland basins and vallevs 

 and on the flanks of the foothill ranges. And this feature is 

 not confined to the East Coast alone — it is equally true of the 

 western portion of the Province of Nelson, and of Westland, as 

 the examples given hereafter will show. 



In North Otago the Waitaki Stone and its associated 

 rocks ascend the Waitaki Valley a distance of over fifty miles 

 from the sea, ending in the Wharekuri basin, which is only a 

 few square miles in extent, being bounded on all sides by 

 steep mountains. Here the Tertiary beds reach a height of 

 over 2,300 ft. above sea-level. 



In the Trelissic basin the Oamaru series rises to a height 

 of 3,200 ft. This basin is somewhat less than four miles 

 square, and surrounded on all sides by steep mountains. 



