No doubt in the post-tertiary period considerable commotions were still disturbing the crust of the earth. The long-continued cooling of the globe produced chasms, fissures, clefts, and faults, into which, very probably, portions of the upper earth may have fallen.
Sin duda, en la época cuaternaria, se verificaban aún trastornos considerables en la corteza terrestre: el enfriamiento continuo del globo producía grietas, sendas, hendeduras por las cuales se escurría probablemente una parte del terreno superior.