About 6900 letters in 28 bound volumes from other officials, assistants, legislators and governors (including many from W.B. Allison and S.M. Cullom) and others, with detailed report-letters about CStL&NO from J.C. Clarke. Enclosures of letters to other officials, advertisements, statements, circulars, etc. included. Some overlapping of dates in volumes. No letters for July-Dec. 1877, July-Oct. 1878, Jan.-Apr. 1879, Feb.-Apr. 1880 and Oct. 1882.