These are primarily scientific letters from Buckland. The subjects mentioned include Milne-Home's seismological investigations, Wheatstone's self-registering instruments, geology (glacial phenomena in Scotland, mineralogy, etc.), numerous references to fossils, and mentions of Mastodon bones and sloths.

A miscellaneous collection of letters written by naturalist Louis Jean Rodolph Agassiz concerning a wide range of topics: natural history and naturalists, geology, mineralogy, fossils, publications, expeditions, and the Museum of Comparative Zoology at Harvard, which he founded.