Lot of 11 Blocks of US Postage Stamps of Science and

Lot of 11 Blocks of US Postage Stamps of Science and Exploration, 498 Individual Stamps, Circa 1950's and 1990's; lot includes; 1) 50 - 4 cent Overland Mail stamps, 2) 50 - 4 cent Silver Centennial stamps, 3) 70 - 4 cent Ephraim McDowell stamps, 4) 50 - 4 cent George W. Norris stamps, 5) 50 - 3 cent International Geophysical Year stamps, 6) 50 - 4 cent Atlantic Cable Centenary stamps, 7) 50 - 4 cent Arctic Explorations stamps, 8) 50 - 4 cent St. Lawrence Seaway stamps, 9) 50 - 3 cent Mackinac Bridge stamps, 10) 20 - 32 cent River Boats stamps, and 11) 8 - 29 cent Theodore von Karman stamps. All blocks and stamps uncancelled and in excellent condition, these have been properly stored over the years.