Figure 1.
Steno’s six-stage model for the formation of the landscape around Florence, involving (1) precipitation of fossil-free sedimentary rocks into a universal ocean; (2) excavation by fire or water of great subterranean caverns; (3) collapse of undermined continents and the inundation of newly formed valleys in a great flood (Noah’s Flood); (4) deposition of layered sedimentary rocks containing fossils as the floodwaters receded; (5) renewed undermining of younger rocks in valleys; and (6) a final round of collapse to create modern topography. Letters serve to identify the same locations or rock layers in successive panels.