1. IOR/V/27/420/73 Reference (shelfmark): IOR/V/27/420/73 Title: India. Survey of India, Trigonometrical Branch Spirit-Levelled heights: Nos 1-6: Madras Presidency 1869-90. Dehra Dun, 1863-1903 Collection Area: India Office Records and Private Papers Languages: English Date Range: 1863-1903 Extent: 1 volume