The journal consists of loose-leaf manuscript, in a marbled board box with leather spine. It is paginated and there are 327 pages plus an additional 19. The title page has the watermark C Wilmot 1835, the remaining pages C Ansell 1876, showing that it was in fact written towards the end of her life, though based on diaries she kept from 1837 onwards. It falls into three sections. Pages 1-69 contain the preamble to the journal. Pages 69-327 are in diary format, beginning 1 January [1837] and ending in 1879. The final section, which is separately paginated, consists of letters to and from the author, copied to augment the narrative. (There are also many letters and poems in the journal proper).
The preamble covers her birth, her early years in America, her father’s re-marriage, the voyage to and arrival in Britain, life at her aunt and uncle’s home in London, travels in Britain and Europe (including the site of the Battle of Waterloo), and her social life in London, beginning with her presentation at court. There are descriptions of many friends - from artists, writers and scientists to French nobility: C R Leslie, G S Newton, the Chalons, David Wilkie, Washington Irving, Samuel Rogers, John Herschel, Achille Murat and Count Survilliers.
In the diary proper JCG records progress with her plays and poems, sometimes noting the start or finish date of a particular work. In addition, she writes of plans for writing projects, as well as what she is reading, lectures attended, various studies (such as the Portuguese language) and translations. She also documents her daily life in London, visits to the theatre (Forrest in Macbeth, Kean in Hamlet), to exhibitions (praise for Turner at the Royal Academy in 1837), to concerts, to parties and dinners (a ball at which Dickens and his wife were present in 1839), and visits to and with friends. She describes her travels in Britain and Europe, often in great detail. Notable is a visit to Cambridge in 1842 (for the installation of the Duke of Northumberland as Chancellor), a tour with the Leslies to Belgium, Germany and Holland in 1844, and the grand European tours between 1851 and 1874 when she spends most of the year abroad visiting the important sites in Italy and France. Interspersed with descriptions of these sites are those of social events (a masked ball at Carnival), religious festivals and ceremonies (she has two audiences with the Pope), adventures en route (she has to cross the river Po on a raft) and people she meets (Gasperone in prison, the sculptress Castiglione). Throughout the diary she records international, national and domestic events: from the Franco-Prussian war to the death of her guardians (the Dunlops), and her reflections on these, as well as those on life and the mores of the time, on the male sex, on literary and public figures - her opinions are forthright and firmly held.
The final section of the journal contains extracts or copies made by JCG of her correspondence with the Carrick Moore family and others.