Korespondencja Ignacego Horodeckiego z Aleksandrem Brongniartem w zbiorach rękopisów Biblioteki Głównej Narodowego Muzeum Historii Naturalnej w Paryży

The article presents the letters of Ignacy Horodecki (1776-1824) to Aleksandre Brongniart (1770-1847). Brongniart and Cuvier used the paleontological and geological specimens sent by Horodecki for the "Description geo]ogique des environs de Paris" [Geological Description of the surroundings of Paris]". The study and comparison of chalk fossils in Poland and France are considered to be crucial for the history of geology. The importance of fossil fauna in dating the various strata was demonstrated for the first time. Horodecki's three letters comment on the circumstances surrounding the sending of the fossils. They also contain information conceming the discovery and analysis of new minerals and the geological structure of Poland, the Ukraine and Lithuania. One of the most important parts of the correspondence between Horodecki and Brongniart deals with the meteorites at Zaborzyca, Brahin and Lidna. Horodecki sent samples of these meteorites to Paris, which were later analysed by Andre Laugier. He also outlines his ideas conceming the origin ofmeteorites, their structure and frequency offalling meteorites. The article presents the translation of alI the letters, as well as information con- ceming Brongniart's responses. The correspondence is ana]ysed for the first time in the light of our current knowledge of geology and the history of science.