Vaal Triangle History
1889 - 1902
Klip Power Station
1939 - 1945
When Leslie rode on horseback along the river bank to inspect the new weir, he came across part of a fossilised forest exposed in the drained river bed below the weir. He saw before him in microcosm evidence of the process, interrupted millions of years before, that elsewhere in the area had been completed to form the seams of coal that Stow had discovered. Hurriedly, Leslie took photographs of the discovery and the prints provide the only record of the forest's existence. Leslie telegraphed the Government geologist, Dr E. T. Mellor, who left his sick bed to hurry down from Pretoria.
Leslie took him straight to the site and both men planned to return the following day to make a thorough examination of the find, but even their preliminary observations were interrupted when a violent storm broke over the area and the river came down in flood. Next morning, the forest was submerged. It will never be seen again because since the
Dr. Leslie: "The river always had a magnetic attraction for me. Often as possible I meandered along its banks to catch a glimpse of its varying moods or to muse on what it might be if it were controlled into a placid stream, such as the upper reaches of the Thames; and if trees could be induced to grow with overhanging foliage, dipping into the limpid water..."
It was Leslie, too, who discovered remarkable collections of Stone Age weapons and implements on various sites on the banks of the Vaal and Klip Rivers which converge at Vosloo Park in Vereeniging. Unquestionably, certain areas of the Vaal River basin were occupied at various times by prehistoric man, and his rock engravings on the outcrops of flat sandstone are still to be seen near the giant Klip power station. Cut with sharp instruments, some of these engravings crudely depict animals, while others are remarkably balanced geometrical designs, the significance of which remains a mystery.
Fossilised plants and fruits preserved in clay deposits for 250-million years have been unearthed in the area and palaeobotanists have learned a great deal about the evolution of certain plants from these finds. Traces of Africa's first insect fruit pests have also been found; and with practically every new excavation made in the area during the past decade precious unknown plant fossils have been revealed. Leslie discovered several of these types which now bear his name: Bothrodendron Leslii, Samaropsis Leslii, Ottocaria Leslii and Argyroderma Leslii are among them. In addition he found several hitherto unknown living plant types of which perhaps the most renowned is Lithops Leslii, the window plant, which together with other specimens are kept