Shoalhaven District Geology

FIELD GEOLOGY OF THE SHOALHAVEN DISTRICT (PART 23) CHAPTER 15: THE CLYDE RIVER VALLEY T aking its rise at an elevation of 2,500 feet near Sassafras, this small river flow south and descends by way of a great canyon to a level of 200 feet at Yadboro. It does this in less than 20 miles, yet it is a further 40 miles to the sea downstream. This is a peculiar result of the dip of the Shoalhaven group sediments. At one time, these must have extended further south than at present. When the area was uplifted, it was tilted to the north, so that the ancestral Clyde River had to erode its bed against this trend.  This undoubtedly led to the formation of many waterfalls and the evolution of the canyon upstream from Yadboro.  The southern edge of the sandstone scarp presents a bold face and is broken into numerous outliers. Some such as The Castle and the Pigeon House are well known to bushwalkers, but there are many others. They all have a similar structure, being capped by cliffs of the...

  FIELD GEOLOGY OF THE SHOALHAVEN DISTRICT (PART 20) CHAPTER 12.  The Milton-Ulladulla District   The Milton intrusion dominates the geology of this part of the country. Its rich soils lie conveniently close to Ulladulla Harbour and settlers began to arrive here about 1830. However, apart from the country underlain by the Milton Monzonite, the rest of the landscape has changed little since Cook first viewed it in 1770.  Apart from the igneous rocks near Milton, The Conjola Formation is dominant in this area. In recent years there has been a revision in the nomenclature of the Formation and it is now known to consist of sediments of widely varying ages, all within the lower Permian. Contrary to earlier ideas, the lower beds are equivalent to the lower part of the Dalwood Group in the Hunter Valley. Some parts of what has been called the Conjola Formation are as young as the lower Maitland Group. Research into this aspect of Shoalhaven district Geology is still in prog...