Новосибирские острова
In 1885–86, with geologist Eduard von Toll (1858–1902), he participated on a scientific journey to the Verkhoyansk region and the New Siberian Islands. On the expedition, they found the remains of mammoths and the fossils of other large mammals, and in the process, demonstrated that the New Siberian Islands had a relatively warm climate during the Late Pleistocene. Eduard von Toll gave the name "Bunge Land" for the low sandy shoal region joining Kotelny Island to Faddeyevsky Peninsula (formerly believed to be separate islands).