250 



Transactions. 



Small rounded grains of quartz are very common, and there are in addition 

 plates of biotite and muscovite, and grains of glauconite and magnetite. 



Marshall (1916) has described a specimen of the Otaio limestone as 

 follows : " A fine-grained type, with many minute quartz grains and a good 

 deal of glauconite. .Mainly Globigerina, but one specimen of Amphistegina." 



The Pareora Beds. 

 These consist of bluish-green clays, which pass gradually up into fine 

 reddish-brown sands and sandstones. Where fully exposed these beds 

 show a total thickness of about 700 ft. Throughout South Canterbury 

 and much of North Otago they are extremely constant in such characters 

 as the bluish-green colour of the clays and the reddish colour of the sands. 

 Again, the lower parts of the red sands always contain concretions, while 

 the middle parts always have many layers of calcareous sandstones crowded 

 with molluscs. Finally, the highest part of the red-coloured beds is prac- 

 tically devoid of fossils, suggesting that the water was so strongly charged 

 with iron as to kill the shell-fish. The change from a blue clay to an 

 iron-stained sand supports the inference that these were the closing members 

 of the series. Thus the great cycle of deposition was completed : con- 

 glomerate, grits and coal, sands and sandstones, marl, glauconitic lime- 

 stone, ordinary limestone, blue clay, red sands. At the Lower Waipara. 

 in North Canterbury, Speight (1914) has shown that the uppermost marine 

 beds are interstratified with gravels. 



Detailed Descriptions by Localities. 

 Otaio Gorge. 

 Here the whole sequence from the quartz grits to the limestone is 

 exposed in a section where the beds are seen dipping E.N.E. at 60°. The 

 field relations of the beds are shown in fig. 3. The grits contain at least 



FNE 



Fig. 3. — Section along Otaio River, near the Gorge. Distance, slightly over 

 200 yards; direction, W.S.W.-E.N.E. ; dip", 60°. 1. Sands and grits 

 with coal. 2. Lowest fossiliferous sands. .'!. Sands with calcareous 

 sandstone. 4. Red sands. .">. Crab- beds with c< >nc id inns (greensands). 

 fi. Grey marls. 7. White flaggy limestone and dark limestone. 

 la. Ordinary limestone. S. Gravels. 



eight coal-seams, of an average thickness of 2 ft. The first of the marine 

 sandstones occur as layers in sandy clays. These clays contain few fossils, 

 but the sandstone is crowded with shells of Cardium waitakiense Sut. 

 and Veneiicardia zelandica (Desh.) var. 



In the sandy clays there are layers of corals, chiefly Balanophyllia hectori 

 T.-W. The overlying crab-beds have even fewer fossils than usual, but they 

 are easily recognized by their colour and their numerous concretions, while 

 an occasional crab may be found. Besides the latter, I collected Pecten 

 huttoni (Park) and Panope sp. The marls, as usual, are practically devoid 

 of fossils. The lower sands and sandstones overlying yielded a rich 

 molluscan fauna, tabulated in column 1 of the table on page 259, and in 



