There are also many 'wild', mainly small caves. The area has possibly as many as 1000 caves and karst features some of which are waiting to be rediscovered such as 'The Catacombs' . The limestone here is only 10m above the water-table resulting in frequent collapses. This restricts the size of the stream caves. Caves are of the small, crawly inclined fissure type.
Caves occur mainly in the western section of the park.
The exception to this rule is Gibb Cave YN 140, entrance to which is gained by a small solution pipe. The cave is large and well decorated for Yanchep and well worth a visit. The almost water-filled Water Cave provides a cooling end to a hot summer's day at Yanchep. A map of Gidgee Karupa shows a little of the detail in the cave. The cave was so named following the discovery of an aboriginal spear shaft in the cave.