. Transactions of the Royal Society of New Zealand. I. Diagrammatic Section and Sketch, North Head, breccia, b. Barren breccia, c. Fine micaceous tuff. d. Lime-stone, e. Greensand. /. Gravel, g. Quarry limestone. The mineral breccia is also exposed on the west sideof the hill forming the North Head, on cliffs near the WaiarekaRiver. Here its relations are not clearly seen, as there is aslide between it and the barren breccia on the south, andit is lost under clay to the north. There is also an exposureof the mineral breccia about two miles north of Kakanuiin a road-cutting (not
. Transactions of the Royal Society of New Zealand. I. Diagrammatic Section and Sketch, North Head, breccia, b. Barren breccia, c. Fine micaceous tuff. d. Lime-stone, e. Greensand. /. Gravel, g. Quarry limestone. The mineral breccia is also exposed on the west sideof the hill forming the North Head, on cliffs near the WaiarekaRiver. Here its relations are not clearly seen, as there is aslide between it and the barren breccia on the south, andit is lost under clay to the north. There is also an exposureof the mineral breccia about two miles north of Kakanuiin a road-cutting (not shown in map) ; it is overlaid conformablyby limestone. On the South Head there are two exposures of brecciabearing the minerals, but their occurrence is somewhat dif-ferent. On the cliffs exposed on the river-bank on the southshore the following section occurs :— 486 II. Section at Cliff on River-bank, South Head, Kakanui. a. Limestone, b. Marl. c. Coralline limestone, d. Tuffs and breccia,e. Hard cap of breccia. /. Limestone, g. Clay. h. Gravel. A limestone of unknown thickness forms the base ; this iscovered conformably by a marl or calcareous mud, 26 ft. thick,the upper 6 in. being coralline limestone ; then follows 60 ft. ofrather fine volcanic tuff containing small cleavage fragments ofhornblende, the top layer of 1 ft. being set in crystalline calcite,rather hard, and containing most of the minerals found else-where in the breccia. This is covered conformably by at least40 ft. of limestone, containing many fossils. Clay then formsthe cliffs to the mouth of the river. An isolated exposureof limestone occurs just at the river-mouth, its relationsbeing obscured by gravel and an artificial breakwater erectedthere. A few yards further on, towards the east, the mineralbreccia occurs again, and forms the cliffs right round the SouthHead for about t
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