Elizabeth Marsh composed the Narrative of her Captivity while living in Chatham (according to a handwritten note in William Musgrave's copy of The Female Captive), around 1760. Her husband, whose mercantile business had failed in England, was attempting to start over in India. In general, this is a calm, straight-forward, geographically-driven narrative with only a secondary emphasis on elaborating details. There are a few vivid descriptions of the captives' physical suffering (long marches in the heat with little water, vermin, and bad food), the sometimes reasonable and sometimes impenetrable behavior of their captors, and of the personalities and households of some Moroccans and transculturated English. Marsh also describes encounters with Moroccan women, and transcribes letter extracts from an English merchant she befriended. Although the author makes occasional appeals for God's protection, particularly in the conversion incident with Mohammed, as a whole the narrative focus is not overtly Christian or religious, though it is certainly hostile to the Moroccan sojourn.

This captivity section of the manuscript appears to be a fair-copy early version of The Female Captive: A Narrative of Facts, which Happened in Barbary, in the Year 1756, published anonymously by subscription in 1769 by C. Bathurst, London. This manuscript differs in several points from The Female Captive. The printed version of her tale is occasionally more detailed than the manuscript, offering specific information on the physical suffering of Marsh and Crisp, the sexual threats Marsh feared from the Moors and Arabs, and Crisp's gallantry towards her. This shift in emphasis may reflect a decision by the author, for reasons Orientalist, commercial, or both, to emphasize (or invent) the romantic aspects of her story. The historian Linda Colley notes that the "considerable" state correspondence around Marsh's very real captivity makes no mention of any sexual threats against her ( Captives 128).

Journal of a Voyage by Sea from Calcutta to Madras, and of a Journey from thence back to Dacca does not seem to have been intended for publication, although the author is obviously aware that someone (family or friends) besides herself is intended to read it. Marsh, by 1774 Mrs. Crisp, had moved to Bengal to join her husband. At the end of the year she took a journey without her family along the coast due to her "extreme ill health." Beginning in December 1774, the author sailed from her home of Dacca (now the capital of Bangladesh), to Calcutta (after 1772, the capital of British India), meeting "my Dear Crisp & sweet Boy" who were there on business. She then sailed further south to Madras, before traveling back to Dacca, often by land. The resulting journal of the trip is a neat, carefully dated document, full of names and places as it charts her movements.

The journal entries are generally diurnal and fairly brief, covering mundane details like descriptions of the weather (awfully hot), when and with whom Marsh breakfasts and sups, and the names of people she meets and whose homes she visits. Overall, more attention is given to the white people she encounters than the native population, although the latter are never entirely absent either, and often register as an ominous, unruly presence. Although she obviously takes pleasure in the varied scenery, even bathing (swimming) as often as she can, the journey is frequently an unpleasant one. Marsh complains steadily of the stupefying heat – at one point she notes the thermometer at 115 degrees [F] – and of her thirst, her inability to sleep or rest because of the heat, and so on. Towards the end of the trip, monsoons appear and make the narrow roads extremely hazardous.

Travel in India was dangerous for reasons beyond the weather as well. On more than one occasion, Marsh's group is harassed by locals, who sometimes demand bribes and sometimes evince physical hostility. British control of India and its population, though being aggressively pursued, was far from complete in 1775. Furthermore, Marsh never fails to visit and comment on every military fort they pass. As in Morocco, she is surrounded by men, but she now travels in a large company which can protect her. The travel train is headed by her cousin, Captain Smith, and features not only several white gentlemen, but also a number of Sepoys and other hired native servants and guards. She has several slave girls and woman servants of her own. The middle-class status which no doubt helped to secure her release in Barbary remains an important part of her identity, as the thrill of adventure is juxtaposed with the trappings of polite Anglo society.