490 Transactions. 



diameter. Garnet, both in combination with other minerals 

 and free, is more abundant here than elsewhere. 



The exposure two miles north of Kakanui showed a limestone 

 resting on the " mineral breccia." The limestone in its upper 

 layers has the characters of the ordinary Ototara stone, but the 

 lowest few feet are more fossiliferous and resemble the Kakanui 

 quarry limestone. This goes to prove that the Kakanui lime- 

 stone is, as Mr. McKay remarks {lot. cit.), a local development 

 of the lower layers of the Ototara stone. The fossils found here 

 were : Flabellum, sp. ; I sis dactyla ; Graphularia, sp. ; Tere- 

 bratella gualteri ; Liothyrina, n. sp. ; Wiyncondla squamosa ; 

 Pecten hutchinsoni ; and Cidaris spines. 



The sequence on the river-bank on the South Head is im- 

 portant as showing that a limestone underlies the volcanic rocks, 

 the limestone forming wherever the sea-bottom was not sub- 

 jected to a shower of cinder from the neighbouring volcanoes. 

 The basement limestone is similar in microscopic structure 

 (sections) to the others in the locality. It contained a few 

 fossils, those collected being Liothyrina, n. sp. ; Pecten, sp. ; 

 and Lamna, sp. 



The overlying marl has few fossils. It would probably be a 

 very suitable material for cement-making when mixed with some 

 pure " white " limestone, but its small thickness and the over- 

 lying gravels would prevent it from proving a cheap material 

 to work. 



The " mineral breccia " in this exposure is much finer in 

 grain than in the others. It contained most of the minerals 

 found on the opposite side of the river, and black mica in addi- 

 tion. The overlying limestone is rich in fossils ; the following 

 were obtained : Liothyrina, n. sp. ; Terebratella gualteri, Tere- 

 bratella aldingi, Magellania lenticularis, Rhiynconella squamosa, 

 Pecten hochstetteri, Pecten yahlensis, Pecten hutchinsoni, Den- 

 talium mantelli, and numerous Cidaris spines. 



The isolated exposure of limestone at the mouth of the river 

 appears to be flat. It may lie on top of the " mineral breccia " 

 exposed a little further east. If, however, it should be the 

 same as that just mentioned, some displacement of the strata 

 must be assumed. 



The development of the " mineral breccia " at the South 

 Head is somewhat like that on the North Head, but the outcrop 

 lines cannot be traced on the beach, because of its steeper and 

 more shingly nature. The inclusions are largest about the 

 middle point of the cliffs. The dimensions obtained were : 

 Hornblende, average, 12 mm. ; black augite, 70 mm. by 25 mm.. 

 60 mm. by 75 mm. by 35 mm. ; feldspar, 40 mm. by 25 mm. ; 

 biotite, 40 mm. by 40 mm. by 12 mm. ; noncrystalline inclu- 



