His paleontological work in the 1790s had established the reality of extinction, which he explained by local catastrophes, followed by repopulation of the affected areas by other species.

• 他在十八世纪九十年代的古生物研究工作已经确定了绝种消亡的事实；他解释说，这是由于局部的大灾难以及随后受影响地区被其他物种重新定居造成的。