This chapter summarizes the facts related to the important changes that occurred in the geological sciences due to the modifications in the basic paradigms throughout the nineteenth century. These changes affected different institutions, although some responded quicker than others to the new situations. The Continental Drift found geologists in Argentina in an advantageous position that allowed them to participate substantially in the development of the new hypotheses. An example of this is the influence that Keidel had on Wegener's ideas regarding the relations between South Africa and South America. Our geologists quickly accepted the displacement of the continents in contrast to those of the northern hemisphere. However, the revolution in Plate Tectonics was not quickly accepted. In this revolution, the paleomagnetic studies of Eng. Valencio were at the frontier of knowledge. Geologists were slower to accept the new hypotheses, but finally recognized them, and played an important role in understanding the mechanisms that led to the uplift of the Andes and in the analysis of processes such as flat-slab subduction, accretion of allochthonous terranes, and crustal delamination and mantle removal.