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number of other smaller exposures along theharbour coast between Karaka and ClarksBeach (Fig. 1). Berry also studied a numberof local drillhole sequences and showed thatthis conglomerate is underlain by earlyPliocene shallow marine Kaawa Shellbed(Opoitian-Waipipian age; Berry, 1986) and isoverlain by widespread rhyolitic pumiceoussands. These latter sediments presumablywere transported down the Waikato River tothis area from the CVZ following the start ofvolcanism in that region sometime after 2 Maago (Briggs et al., 2005). Thus the age of theconglomerate must be somewhere within thelate Pliocene (c. 3-2 Ma ago). This wasconfirmed by the discovery of the leaf of a“brassi” group (large-leaved) beech in one ofthe carbonaceous lenses (R12/f80), a groupthat had largely disappeared from NZ by 1.5-2 Ma ago (Cooper, 2004).Composition and provenance of clasts inconglomerate at Kidds BeachThe conglomerate (and modern beachgravels) is dominated by subangular pebblesof red-brown cherts and greyargillite/greywacke clearly derived from theWaipapa Group (Table 1). The nearest sourceis the uplifted Hunua Ranges, but red chertsare rare in the southern and western partsclosest to Kidds Beach (Schofield, 1976,1979). The greatest concentration of chertunits outcrop in the north-east Hunuas toWaiheke Island area (also the source ofMcCallum’s red chip used widely onAuckland footpaths). The next most commonclasts are more rounded pebbles and evencobbles of cream-white crystalline “vein”quartz. Some of this has inclusions of chertthat link its source to the Waipapa rocks, butother more massive and more coarselycrystalline quartz is more reminiscent of veinquartz typically encountered on CoromandelPeninsula. Other rarer pebble lithologies thatare most strongly linked to a probableCoromandel source are of silicified wood,chert, ?sinter, and silicified flow-bandedrhyolite. Rounded andesite pebbles also couldbe sourced from the Coromandel volcanics,but an equally possible source is the Kiwitahiandesites that outcrop along the eastern sideof the Hunuas (Black et al., 1992). As thecrow flies the nearest andesite source is theWaitakere Ranges to the north-west, but thisseems improbable as it is contrary to thedirection indicated by all the other lithologies.The shape of the pebbles reflects acombination of their hardness, jointing, anddistance transported. The softest and largestclasts are well-rounded but were locallyderived Waitemata Sandstone. The smallestand most angular pebbles are the red cherts -sourced from the hardest and most closelyjointedrocks but transported c. 30 km. Claststransported the furthest (c. 50 km) are thoseinferred to be derived from the Coromandelvolcanic region. These are all the hardestlithologies in the Coromandel Range (freshandesite, quartz, silicified rhyolite and wood)but even so most have been rounded duringtheir long journey. None of the more commonsofter lithologies found on CoromandelPeninsula (e.g. rhyolites, ignimbrites, alteredandesites) are present in the conglomerate andpresumably were not hard enough to survivethe journey. The most convincingCoromandel-sourced pebble has vein quartzand andesite together – a combination notseen in the Waitakere Ranges nor Kiwitahiandesites.Table 1. Character of the cobbles and pebblesin the Pliocene ConglomerateLithology % Size Shape ProvenanceSandstone 30