Sub-series consists of correspondence between Elizabeth Poston and Jean Coulthard recording their friendship and shared professional interests; sub-series also include a copy of "Elizabeth Poston Post-Centenary 2005 Appreciation," which discusses Poston's friendship and correspondence with Coulthard throughout the years. Sub-series are arranged chronologically.

Sub-series consists of correspondence between Jean Coulthard and family members (husband Donald Adams and daughter Jane Adams), and early correspondence addressed to Jean Coulthard's parents, Walter and Jean Robinson. Sub-series arranged chronologically.