In 1929, when already a recognised authority on North African and European Stone Age art, he attended a congress on prehistory in South Africa. At the invitation of prime minister Jan Smuts he returned there in 1942 and took up a chair at Witwatersrand University from 1944 to 1951. During his South African stay he studied rock art in Lesotho, the eastern Free State and in the Natal Drakensberg. He undertook three expeditions to South West Africa and Rhodesia between 1947 and 1950. He described this period as the most thrilling years of my research life. He had excursions to South West Africa and Bechuanaland with a local Archeologist Kosie Marais. In 1953 he announced his discovery of a painting about 6 000 years old, subsequently dubbed The White Lady, under a rock overhang in the Brandberg Mountain.