The earliest item of importance in these papers is a fragment of a diary, partly in pencil, kept by Rockwell in February and March, 1837, when he was locating his property in and around Elkhorn, and is valuable as a record of an early arrival in territorial Wisconsin. Two small diaries for 1848 and 1849 contain, for the most part, memoranda on purchases, the weather, etc. although at the end of the volume for 1848 is a list of varieties of apple trees that he presumably set out on his farm.
Early correspondence is devoted largely to family affairs, routine records of taxation, law cases, and other matters connected with his county offices. Among the letters are a few from persons who took leading parts in territorial affairs, although the letters themselves are relatively unimportant: John H. Tweedy, C. M. Baker, Simeon Mills, and others.
From about 1855 to 1857 there is correspondence on a projected railroad, called the Wisconsin Central Railroad, of which Rockwell was president. Plans were made to extend an Illinois railroad across the state boundary line through Geneva and Elkhorn and thence somewhere in the region of Lake Mills. Information on the project is in the form of mortgage bonds, estimates of finances, and correspondence with bond-holders, promoters, officials of the company, and other railroad companies. Among the writers of letters on the subject are E. M. Joslin of Lake Mills, James T. Lewis of Columbus (later governor of Wisconsin), B. W. Raymond of Chicago who was in charge of the Illinois section of the road, and M. Smith, chief engineer.
There are occasional letters regarding the Elkhorn bank, of which Rockwell was president, in connection with railroad matters and continuing to the end of the collection. After 1860, however, the papers are largely confined to receipts, notes, local affairs, and family correspondence.
