This item contains the following correspondence:

1. 16 December 1976. Typewritten letter to Johnson discussing mineral specimens donated to the Smithsonian collection, an article about australites co-written by Mason, Oliver Chalmers and Ed Henderson, and possible travel to South Australia to study australites in 1977. One page.
   
   
2. 10 January 1977. Typewritten letter to Johnson thanking him for the minerals donated to the Smithsonian collection. One page.
   
   
3. 27 January 1977. Typewritten letter to Johnson discussing Mason's article about australites and the extent of his field research into the occurrence of australites. Two pages.
   
   
4. 7 June 1977. Typewritten letter to Johnson discussing the composition of australites and requesting australite specimens from the area between Wiluna (WA), Ooldea (SA), and Charlotte Waters (NT). One page.
   
   
5. 22 June 1979. Typewritten letter to Johnson discussing planned travel to Australia to search for australites between Charlotte Waters (NT) and Lake Wilson (SA).
   
   
6. 20 December 1979. Typewritten letter to Mason discussing photographs of australites received, the identification of crystals in a meteorite from Nullarbor Plain (SA/WA), and the composition of cometary nuclei as it relates to determining the age of tektites. Attached to the letter is a two page typewritten draft of the letter. Three pages.
   
   
7. 3 January 1980. Typewritten letter to Johnson discussing comet impact and determining the age of tektites, and enclosing an analysis of the composition of a meteorite from Nullarbor Plain (SA/WA). One page.