Letter from Thomas Gold to Dr Arthur A Meyerhoff, Publications Manager, American Association of Petroleum Geologists, 1444 South Boulder, Box 979, Tulsa, Oklahoma 12Is willing to speak on the subject of thermal mantle difficulties inherent in any theory of thermal mantle convection. The other subject, ocean floor spreading, has also puzzled him considerably as he does not understand where the oceans have been contracting, and is disinclined to believe that the entire crustal layer of ocean floors is a recent addition. What he does believe is some recycling in a comparatively thin layer. He also has very heretical views about the origin of the near surface concentration of radioactivity both on the Earth and on the Moon. He is enclosing a reprint about the Moon which is perhaps relevant to terestrial geologic problems. Is also pleased to send a reprint of the beetle, as Meyerhoff does Gold the honour of remembering this from long ago. 7 November 1973