The existence of angular unconformities had been noted by Nicolas Steno and by French geologists including Horace-Bénédict de Saussure, who interpreted them in terms of Neptunism as "primary formations".
A existencia de discordancias angulares fora sinalada por Nicolás Steno e por xeólogos franceses, entre eles Horace-Benedict de Saussure, que as interpretaba en termos de neptunismo como "formacións primarias".