INTRODUCTION
Since its foundation in 1835 the British Geological
Survey (BGS) has had a mandate to provide geological
information on a nationwide basis for the
United Kingdom. From the beginning, attempts
were made to standardize the way in which geology
was illustrated on published maps. Standard symbol
and colour schemes were developed, based on contemporary
classification schemes and reflecting the
conceptual basis for classification. Most of the
schemes failed or had to be modernized. Now that
the digital medium for communicating geological
information is being used increasingly, standardization
of rock and rock unit classification schemes
has become more important. An analysis of past
failures and successes, therefore, should be of considerable
benefit.