In this map from 1967, the contour lines around Myerson Road are wider than before, suggesting that the land on either side had been built up further. The big new building by the blue arrow, the Service Building, was built in the mid-1960s in place of the older structure shown in the 1946 map; notice how the contour lines now skirt the southern edge of that building, suggesting that the whole area had been slightly lowered and levelled to allow construction of such a large structure. Map reproduction courtesy U.S. Geological Survey.