In 1911, Tucan studied the insoluble residue of limestones and dolomites from the Croatian karst realm, and compared it to the composition of terra rossa and bauxite. He concluded that the insoluble residue represented the source material for terra rossa and bauxite, and that these materials in carbonates are authigenic in origin. The provenance study of non-carbonate minerals and other particles based on TUCAN’s (1911) analytical material, stored in Croatian Natural History museum in Zagreb, suggests that they are partly detrital, and partly authigenic in origin