These rocks in Sea Point were visited by Charles Darwin on his epic voyage around the world in 1836 ©Justin Fox
Charles Darwin's Rocks
Location: parking lot at the south end of Queens Beach near the intersection of Beach and Alexander Roads in Sea Point
Whenever there’s a decent swell, surfers clamber over a group of curious, streaky-coloured rocks at the south end of Queens Beach before leaping into the waves. These rocks were visited by Charles Darwin in 1836 during his epic voyage around the world on HMS Beagle.
A plaque in the parking lot commemorates Darwin’s observation that this intrusion of basaltic volcanic rock into granitic rock was a unique geological feature. The plaque also includes a drawing of the Beagle and quotes from his work.
The rocks reveal an impressive contact zone of dark slate with pale intrusive granite. This interesting example of contact between sedimentary and igneous rock was first recorded by Clarke Abel in 1818. It shows how, about 540 million years ago, molten granite intruded into the older, darker, metamorphosed siltstone of the Malmesbury Group of rocks. Although this intrusion initially occurred at great depth, prolonged erosion eventually exposed the granite, forming a basement onto which younger sedimentary rocks of the Table Mountain Group were deposited. This contact was influential in understanding the geology of the Earth.
Darwin’s later account of the rocks at Sea Point (which he erroneously called ‘Green Point’) was a result of eight years of writing and correspondence after his return to England.
The rocks were proclaimed a historical monument in 1953 and a bronze plaque was erected by the National Monuments Council. In 2010 the plaque was stolen for its metal and the City of Cape Town replaced it with an informative plaque describing the significance of the outcrops. Even this new plaque, made of synthetic material, has been vandalised in an abortive attempt to steal it for its ‘metal’ content.