ABSTRACT
The geological problems which interested the pioneers of modern science were chiefly those of geogony, physical geology, palaeontology, and crystallography, or the structure, forms, and properties of crystals. The most fruitful work of the early geologists was in connection with the other groups of problems enumerated above, though the theological presuppositions just mentioned hampered them not a little in their treatment of these problems as well. The most interesting of the early modern geogonies is that of Rene Descartes, who dealt with the problem of the origin of the Earth as part of the problem of cosmogony or the origin of the world. The great geological changes are due either to the disruption of the crust through the explosion of gases inside the Earth or to the action of water flooding its surface. The more scientific departments of geology were greatly advanced and partly started in the sixteenth and seventeenth centuries by the work of Georgius Agricola and Nicolaus Steno.
