Sir Archibald Geikie corresponded with a number of people both socially and professionally. Much of that in this sub-series relates to professional interaction, including geological research and surveying. A number of letters also discuss social engagements and other non-professional matters.

There are a few letters from both Sir George Howard Darwin (1845-1912) and his brother Sir Horace Darwin (1851-1928) as well as larger quantities from palaeontologist Thomas Davidson (1817-1885) and seismologist Charles Davison (Geikie was consulted by the latter regarding financial assistance from the Royal Society for the publication of Davison's The Hereford Earthquake of December 17th, 1896, ( 1898) of which a summary is enclosed). Further correspondents include Patrick Dudgeon of Cargen, who consulted Geikie on geology and mineralogy, and geologist Peter Martin Duncan (1821-1891). There is also a letter from Paul Daubrée informing Geikie of the death of his father, Gabriel Auguste Daubrée (1814-1896).