The British Geological Survey have a number of examples of Google Maps created with OpenGeoscience. OpenGeoscience is data that the society has made available free-of-charge for non-commercial private study, research and educational activities.
Google Maps with WMS
This Google Map is an example of how to use a simple overlay of the society's geological Web Map Service. The map uses 1:625 000 scale data.
ArcGIS Server Extension for Google Maps
Bracknell District Caving Club
This Google Map combines BGS geology with cave information in the Mendips area. It is possible to view the location of caves on the map and select from a number of BGS overlays to show the make-up of the bedrock and deposits.