摘要：On April 5, 2020, our dear friend, Jacek Rajchel (Fig. 1), a warm, smiling and optimistic man, passed away at the age of 76. He was an outstanding naturalist and geologist, popularizer of science, lover of architecture and academic lecturer, devoted to didactic work. He was also closely associated with the Kraków scientific community; a scientist whose research achievements made a huge contribution to the natural sciences.
