My investigation focus was to analyse the pattern on the rocky shore at North Head. A rocky shore is an intertidal area of seacoasts where solid rock predominates. Organisms that live in this area experience daily fluctuations in their environment. For this reason, they must be able to tolerate extreme changes in temperature, salinity, moisture and wave action to survive. The organisms I have chose to investigate are the brown rock shell (Haustrum haustorium), blue banded periwinkle Austrolittorina antipodum and the cat’s eye snail (Lunella smaragda) .