Inter-tidal Zonation — CARNAHAN 
41 
Fig. 5. Vertical ranges of important 
TS Triglochin striatum 
ST Stipa teretifolia 
MO Melarhaphe oliveri 
cs Calothrix scopulorum 
CB Chamaesipho brunnea 
pv Placoma vesiculosa 
RH Rhizoclonium hookeri 
BM Bostrychia mixta 
LP Lichina pygmaea 
SA Salicornia australis 
CN Catenella nipae 
CL Caloglossa leprieurii 
R Ralfsia sp. 
EM Elminius modestus 
cc Chamaesipho columna 
organisms. Significance of key letters 
MN Modiolus neozelanicus 
EB Enteromorpha bulbosa 
MC Monostroma crepidinum 
AS Apophlaea sinclairii 
GP Gelidium pusillum 
AO Avicennia officinalis 
GS Gracilaria secundata 
EP Elminius plicatus 
SG Saxostrea glomerata 
HB Hormosira banksii 
VC Vermilia carinifera 
SA Scytothamnus australis 
SL Scytosiphon lomentaria 
cs Colpomenia sinuosa 
CO Corallina officinalis 
in figure (reading from left to right) : 
CA Codium adhaerens 
SR Splachnidium rugosum 
MC Mytilus canaliculus 
XC Xiphophora chondrophylla 
AN Aeodes nitidissima 
CT Cystophora torulosa 
ZN Zostera nana 
CM Carpophyllum maschalo- 
carpum 
CF Carpophyllum flexuosum 
GK Glossophora kunthii 
CP Carpophyllum plumosum 
ER Ecklonia radiata 
PC Pterocladia capillacea 
PL Pterocladia lucida 
tidal behaviour relative to that at Auckland 
was undertaken at Rangitoto. 
When possible, days of dead calm were 
chosen for tidal readings. The principal sta- 
tion for tidal measurements was the bridge at 
Scoria Flat Inlet, on the southwest shore of 
the island. The times, and heights relative to 
the centre point of the bridge deck, of high 
water under the bridge were accurately de- 
termined on a number of days. No low- water 
readings were possible, inasmuch as the 
Inlet dries out. A reasonable correlation with 
the times and heights of the same tides at 
Auckland was obtained. The vertical distance 
of E.H.W.S.T. below the bridge deck was 
determined, and E.L.W.S.T. placed 12.0 feet 
lower, as at Auckland. This was justified by 
observations of the tidal ranges elsewhere on 
the island. For this purpose tide poles were 
established and the times and heights of high 
