- California Oregon Power Company (1)
- Campbell, Marius R. (Marius Robinson), 1858-1940 (1)
- Canada. Department of the Interior (1)
- Cartes Taride (Firm) (1)
- Chase, Ray P. (Ray Park), 1880-1948 (2)
- Chenault, W. F (1)
- Chicago Surface Lines (1)
- Chicago, Milwaukee, and St. Paul Railway Company (1)
- Continental Oil Company (1)