Sir: This year represents, for scientists, an important double bicentenary - of the death of James Hutton and of the birth of Charles Lyell. These two men, both of them Scots, were the principal founders of the science of geology. At the time of their work, the formation of rocks was considered by some to be a product of great floods or other major terrestrial catastrophes, a consequence of the direct will of God. It was these two who turned wild speculation into good science.

James Hutton (1726-1797) was the first properly to recognise the influence of subterranean heat in the formation of rocks and in their uplift to form land-masses and mountain ranges. These were processes of which he saw "no vestiges of a beginning and no prospect of an end", thus appreciating the great length of geologic time.

Charles Lyell (1797-1875) perceived that, to understand how such rocks as limestones, shales and sandstones formed, it was necessary only to observe the processes in operation in the world around us - the processes of erosion and of sediment accumulation in lakes, rivers and seas. "The present," he affirmed, "is the key to the past." It was through reading Lyell that Charles Darwin gained the understanding of our world that culminated in his great work On the Origin of Species.

Hutton and Lyell, then, were among the greatest pioneers of the earth sciences. At meetings held in England and Scotland this summer, scientists and historians from many countries assembled to commemorate their achievements. Yet, when approaches were made to the British Post Office for the issuing of stamps to mark the double bicentenary, the request was rejected, despite the potential for dramatic and appealing designs that such stamps would have offered.

Instead, the British Post Office has issued a whole set of stamps commemorating Enid Blyton. So it seems Britain is prouder of such a writer than of two world-renowned scientists. Indeed, our values are changing.

Professor WILLIAM A S SERJEANT

Department of Geological Sciences

University of Saskatchewan

Saskatoon, Canada