246 Transactions. 



of the rocks being largely due to the bleaching properties of the humous 

 acids of the soil. Subsidence then ensued, with deposition of marine 

 sandstones which are red in colour, followed by a growth of coral reefs 

 resulting in limestones, the climate still remaining mild. Elevation now 

 occurred, and new terrestrial beds were formed by a rewash of the older 

 marine beds, such rearranged sands with marine fossils being recognized 

 in a bore well at Timaru. The climate now became colder, culminating 

 in a glacial age, during which the older red gravels were accumulated. 

 A warmer period then ensued, during which a soil formed on the older 

 gravels, preserved under the dolerite-flow of Mount Horrible. This was 

 followed by a second glacial age, during which the loess was formed on 

 the surface of the dolerite. 



Thomson in 1914 made some observations on the Waihao district which 

 have an intimate bearing on the neighbouring Pareora district. Briefly 

 stated, he concluded that in South Canterbury and Otago there are not 

 two limestones separated by beds with the " Pareora fauna," as Park in 

 1905 supposed, but one limestone separating two sets of beds with the 

 " Pareora fauna," and suggested that these two similar faunas must show 

 some differences when carefully examined. 



Marshall in 1916 described a specimen of the lower chalky limestone 

 of the Otaio Gorge, and, arguing from the presence in it of Amphistegina, 

 correlated it with the Amuri limestone. Thomson in 1917 disputed this 

 correlation, on the grounds that the Otaio limestone overlies rocks with 

 an Oamaruian fauna, while the Amuri limestone everywhere overlies rocks 

 with a Cretaceous fauna and contains a lower Oamaruian fauna in its 

 uppermost part in the Castle Hill Basin. 



My examination of the district shows that the Tertiary beds of the 

 district are all conformable, and not separable into two unconformable 

 groups as McKay supposed ; that the upper beds with a " Pareora fauna " 

 are above the limestone, and not below it as Park supposed ; and that there 

 is a similar fauna above and below the limestone, as Thomson suggested. 

 I agree further with Thomson that the lower chalky limestone of the Otaio 

 River is not the correlative of the Amuri limestone, but represents a higher 

 horizon. The differences between the fossils above and below the limestone 

 may be gleaned from the tables appended to this paper, but it is not ad- 

 visable to draw far-reaching conclusions as to the zonal values of the fossils 

 which have a restricted range in this district, until similar lists from the 

 neighbouring Kakahu, Waihao, Waitaki, and Oamaru districts are available. 



General Description of the Stratigraphy. 



The complete sequence of Tertiary beds in the Pareora district may be 

 resumed in tabular form as follows : — 



Ft. 

 Red sands and sandstones 400 [ p gerieg 



Blue clay . . . . . . 350 i 



Limestone . . . . . . 80 



Crab-beds and marls . . . . 100 



Lower sands and sandstones . . 100 

 Coal-measures . . . . 300 ) 



This really represents the average thickness as seen in the different 

 localities, but it is probably a low estimate. The blue clay may never be 

 more than 350 ft. thick, but the other members are sometimes much 



Oamaru series. 



