Stamps - Antarctica, British Antarctic Territory an unaddressed envelope with set of fifteen including £1 endurance (franked the last day of use February 14th 1971), unaddressed envelope with set of fifteen 1971 decimal surcharge (franked on the first day of issue February 15th 1971), together with a Royal Research Ship Branfield survey envelope with set of ten stamps and an unaddressed envelope with set of fifteen 1973 issue (franked on the day of issue 14th February 1973), all franked Base Z, Halley Bay