THE GEOLOGICAL WORK OF THE BAUDIN EXPEDITION IN AUSTRALIA (1801-1803): THE MINERALOGISTS, THE DISCOVERIES AND THE LEGACY

The Baudin expedition to Australia included among its scientific staff Louis Depuch and Joseph Charles Bailly, the first professionally educated geologists to visit this country. Together with the zoologist Francois Peron, they carried out the earliest geological surveys along large parts of its coast. Their views on the origin of the major rock types were mainly guided by Neptunist thinking. However, in line with the beliefs of a number of French geologists at the time, they recognized basalt as a volcanic rock. Their identification of earth materials was hampered by the still imprecise definition of the physical properties of minerals and rocks. Their work provided the first detailed descriptions of the major rock types and their distribution along the margins of the continent and its islands, and led to some tentative conclusions with regard to the presence of mountains in the country's interior. The three investigators concluded that Australia was built on a foundation of granite, overlain by a variety of sedimentary rocks and fringed by extensive deposits of largely unconsolidated sediment, left behind by a retreating sea. Their mistaken identification of dolerite as basalt led them to believe that they had discovered evidence of volcanic activity in Australia. Issues such as the presence of marine organisms in rocks now above sea level, and the finding of various species of mollusks on Australia's shores, known to be extinct in Europe, led to lively discussions among a number of European naturalists.