This collection consists of 23 letters, five newspaper clippings, and six miscellaneous items. Nineteen of the letters are addressed to Cora Clarke, with four to her mother and one to her father. No single correspondent or time frame dominates the collection, nor are there themes which run through all the letters, except in the most general sense. Prominent people represented in the collection as correspondents include Grace Greenwood (a.k.a. Sarah Jane Clarke Lippincott), Jacob Abbott, James Freeman Clarke, Edward Sylvester Morse, Alpheus Spring Packard Jr., Robert Collyer, Samuel Eliot, Francis Parkman, and Elizabeth Cabot Cary Agassiz.
The Clarke Papers appears to consist largely of letters retained for their autograph value, more than their substance. Clarke's botanical and entomological activities appear most clearly in letters from the Cambridge Entomological Club (1878 November 16) and Francis Parkman. However, only Charles Russell's letter discussing the anatomy of flowers (1870 December 19), provides anything approaching a lengthy or in-depth discussion. More typical are a letter dated 1875 May 25, mentioning the Boston Society of Natural History and the "Society to encourage studies at home," and a receipt for a summer botany course (1874 August 4) suggesting Clarke's commitment to continuing education. The value of the collection lies primarily in creating an impressionistic portrayal of a respected female scientist at a time when she was maturing into adulthood.