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Rock fold in the sandstone and metamorphosed red siltstone viewed from lookout below Boyds Tower

The Pinnacles formation consists of cliffs of soft white sand capped with a layer of red, gravelly clay. The rusty-red colour is caused by iron oxides
The axial surface of the fold is also a fault which has displaced the beds east side up

Ben Boyd National Park

Latitude -37.105027, Longitude 149.951148

Located in the Sapphire Coast Region of NSW, nearest town Eden

Source: and


Link to Detailed Map

The landform of the Ben Boyd National Park rises gradually from the coast to a ridgeline along the western boundary. Most of the southern section of the park is less than 160 metres above sea level and the northern section less than 100 metres above sea level. There are steep slopes in a few places, particularly east of Haycock Hill and along the descent into Disaster Bay. The park divides quite neatly into two geological zones: sedimentary rocks which outcrop in the north and much older metamorphic rock in the south

During the Devonian period from 410 million years ago to 345 million years ago, sediments similar to those in the northern section of the park were laid down in non-marine environments. Later these were compressed, heated, folded and twisted into arches and curves. The soft sediments hardened and formed new types of rock, for example: red, brown and green shales; sandstones; siltstones; conglomerates and quartzites. Most of the park lies on these rock types. They are exposed along the cliffs and headlands of the coast as far north as Terrace Beach, and from Haycock Point westwards along the Pambula River estuary. The folded, Devonian strata are an important landscape feature of the coastline.

More than 80% of the Upper Devonian rocks exposed along the coast of south-east Australia are found in Ben Boyd National Park. Superimposed on the Devonian strata are much younger and softer Tertiary sands, gravels, clays, ironstones and quartzites of the Long Beach formation and Quondolo formation. These cover much of the northern section of the park and have formed the long sand ridges of Long Beach. Relatively small areas of Tertiary deposits are scattered along the coastline of the southern section of the park.

The Pinnacles can be accessed from Haycock Road which leads to the east from the Princes Highway between Pambula and Eden. A walking track from the car park leads to the formation. They were formed by erosion of the finely mottled well lateritised Pinnacles Lens of the Long Beach formation. This formation consists of cliffs of soft white sand capped with a layer of red, gravelly clay. The Pinnacles form the side of a steep gorge that contains features typical of areas of high drainage density. Laterites are soil types rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are rusty-red because of iron oxides. They develop by intensive and long-lasting weathering of the underlying parent rock. Tropical weathering (laterization) is a prolonged process of chemical weathering which produces a wide variety in the thickness, grade, chemistry and ore mineralogy of the resulting soils.

At Red Point, from a viewing platform just below Boyds Tower, you can see an excellent example of a heavily folded metamorphic bed. The axial surface of the fold is also a fault which has displaced the beds east side up. The rock platform on the southern side of Saltwater Bay also has one.

North of Pambula Beach lies the southern extent of the Merimbula Bay barrier dunes which began accumulating 7000-8000 years ago and stabilised in their present form about 5000 years ago. This regionally significant dune system is one of only four major stationary barriers in southern NSW, and is an excellent example of this type of formation.

Getting There

The Ben Boyd National Park lies between Pambula and Wonboyn Lake on the far South Coast of New South Wales. It is accessed from the Princes Highway by either Haycock Road or Edrom Road.

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