Giovanni Targioni Tozzetti

Giovanni Targioni Tozzetti (Florence, 11 September 1712 - Florence, 7 January 1783) was an Italian naturalist. He was supervisor of the Orto Botanico di Firenze in Florence succeeded by Saverio Manetti. Apparently met Caso Umbria in the 1730s. After the age of catastrophic, to give strong evidence on geomorphological activities occurring on earth, he postulated that the irregular courses (symmetry and asymmetry of the valleys) of the rivers depended on the nature of rocks through which they flow. The regions of massive and resistant rocks maintain deep and narrow courses (valleys) whereas broad and meandering courses are developed in the regions of soft and less resistant rocks. Thus, this concept gives the glimpse of differential erosion.

Portrait. Credit: Wellcome Collection