9/2/033/3-124

The rocks of the Karoo Supergroup are key to the understanding of the early evolutionary history of the major groups of land vertebrates including mammals, reptiles and dinosaurs. These Karoo rocks are several thousands of metres thick covering almost 2/3 of the surface area of South Africa and contain an unrivalled wealth of fossils reptiles which lived more than 200 million years ago.

The remarkable aspect of the Karoo rocks is that they hold a largely unbroken record of prehistoric life extending from the Permian to the Jurassic period (from approximately 300 to 200 million years ago). The flood planes of the Beaufort Group provide an internationally important record of life during the early diversification of land vertebrates. This time period was crucial in the development of reptiles and higher forms of life as it was during this time that the reptilian lineage split and evolved into the various groups of reptiles which exist today. In the rocks of the Karoo are found fossils of the ancestors of lizards and snakes, tortoises, crocodiles and dinosaurs. 

However the fossils for which the Karoo is best known internationally are the mammal-like-reptiles (therapsids), so called because they are reptiles which show features of mammals and represent a transitional stage between reptiles and mammals. In 1934, Dr Robert Broom, a palaeontologist of international repute, wrote "the mammal-like reptiles from South Africa may be safely regarded as the most important fossil animals ever discovered, and their importance lies chiefly in the fact that there is little or no doubt that among them we have the ancestors of mammals, and the remote ancestors of man".

The Gats River bed is one of the most productive fossil sites in the Beaufort Group in South Africa and is always a good destination to take student excursions as one is assured of finding fossils. The site has long been known to be productive for fossils and has been collected by distinguished palaeontologists including Robert Broom, Croonie. James and Ben Kitching.