The Correspondence: Joseph Wilson Lowry to HR Mill sub-series consists of:

Notes for 4 lectures on the 'Volcanic History of Britain', given to the Royal Institution in 1886. Sir Archibald Geikie looked at the emergence of types of geological formations against a geological timeframe and how they have been affected by various processes, especially the action of volcanoes and materials produced by them, within the natural world. He used examples from numerous locations from different parts of the British Isles.

Letter to Robert Boog-Watson from Sir Archibald Geikie. Geikie discusses Boog-Watson's geological mapping of the south end of Arran and compares it with his own mapping of the Isle of Bute, the Cumbrae Islands, Renfrewshire and Ayrshire. He discusses Scotland's old red sandstone unconformity. He extends an invitation to join him in mapping Tinto Hill as soon as his expected working visit from Lennox is over.

Letter to Robert Boog-Watson from Sir Archibald Geikie thanking him for his gift of figs and telling him that his diet is currently restricted due to ill health. He reports on a difficult visit from Sir Andrew Crombie Ramsay. He discusses the geological unconformity of the south end of the Isle of Bute and includes a sketch cross-section.