The collection contains six letters (ALS) from Seth H. Tyson, a young man from Philadelphia, mostly to his mother, concerning his California Gold Rush experiences in Calaveras County, 1853 and 1855. Early 1853 letters talk about working in San Francisco and on farms, but later ones mainly concern Tyson's prospecting ups and downs, the hard work, problems with lack of water in the rivers, difficult financial dealings, and general uncertainty of life in the gold fields. The collection also includes typescript transcriptions of the letters.