488 Transactions. 



being 14° at its contact with the fine tuff. The top layer, as 

 stated, is fossiliferous, and appears to have formed the sea- 

 bottom for a sufficient time to permit of a growth of corals. 



The chief fossils found here were : Corals — Flabellum cir- 

 culare and other species ; Trochocyathus, sp. ; Deltocyathus, sp. ; 

 Amphihelia intricata ; and Graphularia, sp. Brachiopods — 

 Magellania lenticularis and M. sinuata ; Liothyrina, n. sp. ; 

 Notothyris suessi ; Terebratella gualteri ; and Rhynconella squa- 

 mosa. Scaphopods — Dentalium mantelli. Gasteropods — Scalaria 

 brownii ; Siphonalia nodosa ; Mitra, sp. ; Gibbula, sp. ; Turbo, 

 n. sp. ; Natica, sp. Lamellibranchs — Cardita, n. sp. ; and Pecten 

 sectus. Cephalopods — Nautilus, sp. 



The fine micaceous tuffs are poor in fossils, and apparently 

 represent a period during which the ocean-floor was being 

 covered with fine detritus from some neighbouring volcano. 

 The " mineral breccia " contains very little mica ; none was 

 found on the sea side of the North Head, and but little on the 

 side next the river. More was found on the South Head in 

 both exposures, but the small amount renders it improbable 

 that these tuffs could have come from the eruptions causing 

 the " mineral breccia." 



The limestone overlying the micaceous tuff is, on the beach, 

 poor in shells, being made up largely, as microscopic sections 

 show, of Foramintfera and Bryozoa. The following genera 

 occur : Textularia, Rotalia, Nummulina, and Globigerina. 



On the top of the hill forming the North Head, however, a 

 limestone of a different nature, but evidently stratigraphically 

 the same, occurs. It appears to be composed almost entirely 

 of Brachiopod shells, the shells themselves and the spaces between 

 them, however, being filled with the same genera of Foraminifera 

 and Bryozoa as occur on the beach limestone. It is thus referred 

 to in the Geological Survey Reports (1883, p. 63) by Mr. Mc- 

 Kay : " Kakanui Limestone : This forms an isolated hill near the 

 Township of Kakanui. The limestone is full of shells, mostly 

 Brachiopoda, and thus differs greatly from the ordinary Ototara 

 stone, which is usually poor in such forms. In former reports 

 it was referred to as a Tertiary rock, but closer examination 

 and a large series of fossils collected show it to belong to the 

 lower part of the Ototara stone. The Brachiopoda collected in 

 great part belong to Terebratida, Terebratulina, and peculiar 

 forms of Terebratella not found in New Zealand Tertiary rocks." 



The limestone here appears to be slightly more crystalline 

 than in other parts, and breaks more readily across the middle 

 of the Brachiopod shells, thus exposing the brachial arms and 

 allowing of certain determination of the genera. Besides this, 



