More evidence of the effects of geological folding can be seen between South Hook Point and Gelliswick Bay. The Old Red Sandstone sequence here has been examined in great detail by geologists who are studying the ancient environments in which these rocks were formed.

Within the stones there are large, in-filled burrows of amphibious creatures, and fragments of primitive armoured fish have also been found.

Looking over to the opposite side of Sandy Haven, at Little Castle Head (near the navigation marker tower) the tightly folded rocks include layers of volcanic ash.

The forts were built in the 1860's as part of the 'Palmerston Defences'. They are Victorian Forts built on the recommendation of the Royal Commission in 1860 in response to the earlier Napoleonic Wars (1803 - 1815). They include Dale Fort, Stack Rock Fort, Chapel Bay Battery, South Hook Fort, Thorn Island Fort, and East and West Block House Batteries.

Although the pipelines may appear to be an unlikely habitat for wildlife, Cormorants and a variety of gulls love to sit here. Beneath and between the two jetties, there is an extensive community of eel grass that flourishes in this shallow sheltered environment, which is also home to a specialist red algae.