Geological Conservation Review (GCR) sites are selected for,
and grouped according to, GCR blocks, which are site-selection
categories for nationally important Earth science sites.
There are around 100 'blocks' and about 3,000 GCR sites in
Britain. Each 'block' represents a particular geological age
or Earth science theme, such as Marine Permian Stratigraphy,
Jurassic–Cretaceous Reptilia, Caledonian Igneous Rocks and
Quaternary of Scotland.
Geomorphology blocks cover the history and development of
landforms and geomorphological processes active today, for example,
rivers, coasts and landslides. Unlike geological sites where
processes can only be inferred, active geomorphological sites
provide open-air laboratories where processes can be studied.
Because geomorphology influences landscape and habitat, there
is great potential for integrating the physical and biological
components of nature conservation in geomorphological sites.