Fonds consists of records created and collected by Agnes Effie Sands Mern and other members of the Wawanosh family. Included are records relating to the life and work of various family members. In particular, the fonds contains records relating to the work of Joshua, David and William as chiefs of the Chippewas of Sarnia. Also included are the personal records of the family including correspondence, financial records, memorandum and account books and personal records relating to births, marriages and deaths. The records of most of the family members are intermingled, possibly a reflection of how Agnes Sands Mern kept them. Also included are the records of Agnes Effie Sands Mern (which make up the majority of the fonds) including her correspondence, financial records (including the records of the Wawanosh Post convenience store), records relating to her musical and artistic interest and records relating to her work in the Church and her activities organizing cultural events and concerts. Also included are the records of Agnes' husband John Phillips Mern such as his correspondence, financial records, notebooks and personal records relating to his son John P. Mern Jr.
Fonds also contains several sketches of members of the Wawanosh family as well as a large assortment of photographs. Photographs include portraits of family members, ministers and missionaries, friends and others as well as images depicting the daily life and travels of Agnes and John P. Mern. Photographs of John P. Mern consist of several albums documenting his time in the US navy and the childhood of his son. Several photographic processes are represented including tintypes, cartes de visite, cabinet cards, postcards and prints.