Thanks Dennis! The place is geological wonderland.
Did a bit of a hunt for information this is what I found:
The geological makeup of Bouddi National Park is characterized by fascinating features that have evolved over millions of years. The park’s landscape comprises sedimentary rock formations, primarily sandstone, shale, and conglomerates, which originated from sediment deposits by water flow through creeks and rivers. This process occurred approximately 200 to 290 million years ago when the area that is now the Bouddi Peninsula was located inland.
The prevalent sandstone found in the region is known as Hawkesbury Sandstone, which forms the upper layers of the hills. Beneath this sandstone lies the Gosford and Terrigal Formations, consisting of softer sandstone, shale, and ironstone—a mixture of sandstone, clay, and some conglomerate. These rocks have been continuously shaped and altered by natural forces such as water, wind, and temperature changes, leading to the diverse terrain we see today.
Erosion and weathering of these rocks have also played a significant role in shaping the current landscape and have contributed to the formation of soils in the area, including sand, loam, and iron-rich laterite. The laterite soil at Killcare Heights is particularly noteworthy. It has developed over time as the surface sandstone underwent weathering and chemical leaching, resulting in a red, soft, and crumbly soil that hardens when exposed to air.
The park’s geology not only contributes to its stunning landscape but also influences the type of vegetation and the variety of animal habitats in the area. The geology and erosion have also led to the formation of unique features like tessellated pavements, visible on the coastal walk from Putty Beach to Bullimah Beach, which are formed by the expansion and contraction of clay.
These geological processes have been ongoing for millions of years, sculpting the Bouddi Peninsula into the spectacular coastline we see today, complete with headlands, rock platforms, bays, beaches, dunes, and lagoons