A Dip Into The Past: Coogee 1959
Each January for the past 10 years or so, Sydney’s Randwick Council invites me to conduct a community excursion along the coast around Coogee. This is a two hour walk from the beach along the cliffs to the south towards Lurline Bay. I feel very privileged to be able to share my knowledge of its geology, geomorphology and general history, and to learn from locals what they know about the area. It is a coastal place that has directly influenced my career as here I undertook my first systematic piece of coastal research.
The geography undergraduate honours program at Sydney University in the 1950s into the 60s allowed third year students studying physical geography to undertake a field assignment during second term. In 1959 Trevor Langford-Smith ran a coastal course and encouraged/directed us lucky participants to select part of Sydney’s coastline to study. In later years locations spread farther afield such as Macmasters Beach on the Central Coast which Andy Short studied. Coogee was available for me so during April and May 1959 I spent quite a few days doing field work as well as talking to locals and visiting the Randwick Council library. It was exhilarating.
As background to this study, Trevor invited us to read widely on coastal landforms. At that time beach literature was sparse compared to what existed on rock platforms. The Geography Library had a wonderful journal collection including a set of the Journal of Geomorphology (1938-45). This journal was edited by the famous American coastal geomorphologist Douglas Johnson so naturally the proceedings contained quite a few coastal papers. Johnson himself had visited Sydney in 1931. Several key papers on platforms from different parts of the world are in this journal. They still get cited today as seminal works on platform development. Of particular note was the paper by Wentworth in the first volume on water-layer weathering processes as described from his work in Hawaii. But in 1939 Jutson published on the Sydney rock platforms. He was not the first but his paper stimulated my thinking at the time.
Recently I discovered all my notes from this reading as well as field notes (with maps and sketches), and a scribbled draft of the assignment. Sadly the final report with photos submitted for examination is lost. Nevertheless it was like magic to find what I had observed so many years ago and what I inferred from those observations.
The field study involved four elements. First, to collate local information from sources such as onshore geology and offshore bathymetry (to which was added engineering information from the Council). Second to observe wave action at different tides on the beach and onto the rocky shores. This provided me with an appreciation of wave refraction and breaker types which I had just started reading about. Third was the detailed mapping of rock cliff and platform features from Gordons Bay in the north to Lurline Bay in the south. Sites were numbered along this stretch from 1-18 for detailed description. And fourth, an attempt to place these observations into the context of platform evolution as described for the Sydney area and beyond.
I had forgotten so much of what I did at this time. It was pleasing to see I was asking myself lots of questions. Trevor encouraged this very open approach. He admitted at this stage of his career that he was not familiar with coastal literature or field studies (he had a soils and fluvial background with CSIRO). It was important to not generalise from one or two sites hence the need to walk the entire stretch noting variations in the lithology and structure of the Hawkesbury Sandstone, the role of differential rock hardness, the undercutting of “softer” rocks, the talus blocks and of course, the micromorphology of platform surfaces such as potholes. As reported by Johnson, Jutson and others, it was difficult to interpret the role of higher sea levels in platform formation given the range of elevation of platform benches. I had to consider specific geological controls (e.g. dykes and joint patterns), and operation of different wave, wind and runoff processes. I could not find anything like the c.5m relic potholes reported by Maze in 1933 from Green Point, Broken Bay. However, I took an agnostic view on the role of higher sea levels even towards a so-called “raised beach” in Gordons Bay (which contained bone material). And I did learn about operations of the Council in dynamiting dangerous overhanging rock ledges north of Giles Bath, Coogee.
Looking back I feel quite satisfied with this initial effort in field work, especially in the attention to detail and preparedness to make inferences on what remain as complex issues. It is now time to renew our efforts on understanding the genesis of the cliffs and platforms. Andy Short, John Hudson and I have just completed a paper to be published soon in Journal of Coastal Research. This paper is one of three we are working on related to rocky shore and continental shelf formation also involving Peter Cowell and Mike Kinsela. For Andy and me it brings us full circle from our early explorations stimulated by Trevor at Sydney University to the present. Collectively and with other students we have enough material to again engage in debates on rocky coast evolution.
Each time I return to Coogee for the summer field trip I think back to those early days of field work. To discover those old notes has been quite a revelation adding to information I can use in future community walks.
Bruce Thom
Words by Prof Bruce Thom. Please respect the author’s thoughts and reference appropriately: (c) ACS, 2025. For correspondence about this blog post please email admin@australiancoastalsociety.org.au
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