The morphology of beach cusps on a number of beaches around the South Islan
d, New Zealand is described. Cusp dimensions such as spacing, elevation, am
plitude, depth, and spacing variance are interrelated. Cusp dimensions co-v
ary in regular fashion under different process conditions, such that the cu
sp form displays a high degree of regularity. Beach cusp amplitude is an ex
ception to this regularity, that appears to be controlled by factors such a
s grain size and beach slope. Analysis of cusp spacing and elevation dimens
ions on mixed sand and gravel beaches reveal that cusps having particular s
pacings form at distinct elevations on the beachface, with the largest spac
ings occurring at the highest levels on the beachface. The relationship bet
ween cusp elevation and spacing provides a technique through which beach cu
sp spacing can be used to infer mean sea-level. (C) 1999 Elsevier Science B
.V. All rights reserved.