420 Transactions. — Oeology. 



palagonite. I could obtain no direct evidence of the age of 

 these rocks, and it is quite possible that the andesitic lava 

 flows may belong to a later period than the palagonite tnflfs. 

 This is a point that requires more investigation than the time 

 at my disposal would allow. 



4. Kakanui Volcano. — The Kakanui River runs into the sea 

 between two low hills formed of scoriaceous sandstone overlain 

 by the Ototara limestone, here generally more compact than 

 usual. (Section IV.) The sandstones of the northern hill 

 form a periclinal curve, which extends across the river so as to 

 include the rocks seen in the river-bed between the bridge and 

 the sea. The south head is a separate and smaller periclinal 

 curve, showing two foci of eruption ; but I did not ascertain 

 which of the two is the younger. I saw no lava streams. 



Sedimentary Rocks. 



Ototara Series. — This series consists of the Ototara lime- 

 stone, known as the Oamaru building-stone, together with all 

 the conformably underlying rocks. The Ototara stone is a 

 rather friable and very pure limestone, capable of absorbing one- 

 third its bulk of water. It is made up of minutely comminuted 

 Bryozoa and Hydrocorallin^e, with Foramiuifera in the interstices. 

 The underlying beds differ in different places. In Cave Valley 

 the rocks immediately underlying the limestone are obscured; 

 but the railway passes through a bed of pale-yellow, non-cal- 

 careous, diatomaceous ooze, which is cut by a dyke 20 feet 

 thick and running E.N.E., with a dip to N.N.W. (Section V.). 

 This dyke is a compact, very dark basalt, without olivine, but 

 with aggregations of greenish-brown augite grains with felspar 

 laths, giving it a semi-ophitic texture. S.G. = 2-80. The dyke 

 does not penetrate the Ototara limestone ; but this cannot be 

 taken as positive proof that it is older than the limestone, for 

 its upper termination is not seen. I did not observe the chalk 

 marl with flints, mentioned by Mr. McKay. 



Furtlier down the valley, at the School, volcanic rocks under- 

 lie the ooze. These volcanic rocks are seen in many places m 

 the Waireka Valley below the Ototara limestone, and I have 

 never seen any above it. In 1874, 1 observed, in a valley a little 

 south of Cave Valley, thin-bedded, hard, dark sandstones under- 

 lying the Ototara stone. I believe that these beds come in 

 between the limestone and the diatomaceous ooze, but I could 

 not find them again this time. About a mile and a half south 

 of Cave Valley the following section may be seen : — 



6. Ototara limestone. B. Palagonite tufl". 



5. Clay. 2. Diatomaceous ooze. 



4. Tutfaceous clay. 1. Volcanic rocks. 



The lower part of the limestone contains small rounded frag- 



