Below is a list of general geological resources that might be of use or interest.
Geo-nealogy, or Where Do You Think You Were?
For those wanting online geological maps of the UK, the Geology of Britain viewer (BGS Open Geoscience) can be found here.
The Geological Society’s Brief Summary of British Stratigraphy can be found here.
A good overview of the geology of Plymouth (which helps make sense of the confusing geological map) can be downloaded here.
Online geological map resources for the USA (courtesy of the US Geological Survey) can be found here.
An online, interactive geological atlas of New Zealand can be found here.
Other useful links:
If you’re having trouble with all the different names for different intervals of geological time, the GeoWhen database is very useful. It aims to clear up the confusion over regional, national and archaic terms, and can be found here.
GeoScenic, the National Archive for Geological Photographs, can be found here. You can search for, view and download thousands of images from the vaults of the British Geological Survey.
The GCR (Geological Conservation Review) database can be found here. You can search for national geological sites of importance, some of which (e.g. Flamborough Head) have site accounts providing details on the geology of that locality.
The GCR also has an Image Bank, where the photos and figures from many of its geological volumes are available. These vary from British Silurian Stratigraphy to the Quaternary of the Thames, via the Fossil Reptiles of Great Britain. The full list of available volumes can be found here.