Includes: a manuscript account of a tour by yacht on the Norfolk Broads, perhaps by Huia Onslow's governess Helen Moodie; several items from Onslow's time at Eton College, such as a printed programme for an Eton College Scientific Society Conversazione, in which Onslow features as demonstrator and lecturer and two copies of another lecture given by Onslow.
There are also pieces of creative work such as a poem, The Story of the Lost Ice Age, written at Eton for a prize, and a draft of a story, The Sobbing Water. Poems appear too with notes on ascents of the Croda del Lago and lists of books about the Dolomites, showing Onslow's interest in mountaineering. Also present are Onslow's translations of poems from Les Amours de I. du Bellay, by Joachim du Bellay, which according to the memoir published by his wife he was thinking of publishing in 1913-1914.
Two items are posthumous: the order for the memorial service for Onslow held at Trinity College, Cambridge in October 1922, and uncut proofs for first chapter of Huia Onslow: a Memoir by his wife Muriel Onslow, published in 1924.