The Isaac Bullock papers contain personal manuscripts, copies of correspondence, and a photograph of former Salem resident, Captain Nehemiah Haskell. The collection has been divided into three series.

Series I. Manuscripts contains a bound manuscript volume Notes and Reminiscences: Spunyarn of Rhythmic Sketches, Prose Notes, and Musings of an Old Salt. Subtitles to this manuscript include: Scraps of Voyaging, Mining, Travel, What a Sailor Saw and Thought, Like a Log Book-Brief and Pointed, Short Yarns to Spunyarn Wrought, By Knotting all Together, and To a Volume Brought. It contains several flyleaf pages, including a photograph of the author (page IXX), and several appendixes. The manuscript was originally bound April 1864, but contains many added notes and annotations dated until 1870. Bullock dated and attributed these notes and annotations to "IB" (Isaac Bullock) and frequently highlighted his comments regarding points in the text with "NB" (nota bene-note well). There are 101 chapters or sections in the volume dealing with subjects as diverse as the American Civil War, the Puritans, comments on flora and fauna, history, gold prospecting, travels, insights on Milton's Paradise Lost, etc. Included are numerous illustrations, photographs, and drawings, many by the author. These include ships on which he served, sketches of places, people, flora and fauna, as well as a colored drawing of the Trask homestead. As in Bullock's other manuscripts, this work contains both poetry and prose. Bullock commented that the work was put together during the last few years of his mother's life. At her request, he remained at home with her and occupied much of this time writing the volume. This series also contains a collection of nine leaves of manuscript poetry with quotes and adaptations, with ink illustrations; a commentary, and other notes on Isaac Bullock's family genealogy and the history of Salem, which were purchased separately.

Series II. Correspondence contains two typescripts of letters from Isaac Bullock to his mother written from the gold fields in 1851. The California Park Service found these typescripts in the pioneer files of Sutter's Fort, California, in Sacramento. The letters were transcribed and sent to Salem, Massachusetts' Chamber of Commerce in an effort to gain more information about the individuals associated with the material. The original letters are dated January 20, and March 25, 1851. In the first letter Bullock mentions several Salem men who were in the Salmon Fall area: Captain Nehemiah Haskell, James Phelps, James Chase, and William Russell. Additionally, he mentions the costs of provisions and the cost of getting his prospecting gear together. In the second letter he describes the scenery, as well as further comments on provisions. In each letter he informs his mother how much gold he had sent home to her. The gentleman at the California Park Service also copied an unsigned note that was attached to the letters when they were found. This note gives a brief biographical sketch of Isaac Bullock, particularly regarding his travels to California and getting started in prospecting; its original source is unknown.

Series III. Captain Nehemiah Haskell contains a photographic copy of a portrait photograph of Captain Nehemiah Haskell. The original photograph was copied from the family album of a granddaughter of one of Haskell's old friends and neighbor at Salmon Falls; this copy was included with the letters sent by the California Park Service.