This collection consists of two subgroups. The Charles William Gross subgroup contains general correspondence (1920-1927), which pertains primarily to Gross' search for career advancement; miscellaneous correspondence (1928); financial records (1926, 1928), printed material; reports (undated); writings (1924, 1927) regarding Montana oil refineries and wildcat operations in the state; miscellany (1921-1930), containing statistical information (much in graph form), regarding Montana's oil industry, as well as material reflecting Gross' tenure with the railroad companies. The Nashua Oil and Gas Company Subgroup contains incoming correspondence (1923), financial records (1923- 1930), legal documents (1930), maps, minutes (1930), and organizational records (1923-1924).