- M. & H. Marcus (Breslau) (1)
- M. Badiola y Cia (Lima) (2)
- M. Carey & Son (Philad[elphi]a) (1)
- M. Carey & Son (Philadelphia) (1)
- M. Carey & Son; Philadelphia, Pennsylvania (1)
- M. Carey (Philadelphia) (3)
- M. Carey (Philadelphia, Pa.) (1)
- M. Carey and Son (Philadelphia) (1)
- M. Carey and Son; Philadelphia (1)
- M. Dripps (New York) (1)
- M. Gomez (Lisboa) (1)
- M.I. Weller (Washington?), 1901 (1)
- Maclear & Co., Liths (Toronto) (1)
- Madison Association of Commerce (Madison, Wis) (1)
- Major & Knapp Eng. Mfg. & Lith Co (New York) (1)
- Mangum & Josephine Weeks (Alexandria) (1)
- Marshall County Land Co. (Warren, Minnesota), 1906 (1)
- Maryland Geological Survey (Baltimore, Md.?) (1)
- Maryland Geological Survey (Baltimoré) (1)
- Maryland Historical Society (Baltimore, Md) (1)
