Geological Conservation Review. The GCR was initiated by the Nature Conservancy Council (1977) to assess and document the most important parts of Great Britain's rich geological heritage. Sites were selected based on the importance of the geology shown therein, with an attempt to select those with the most important, exceptional and representative geology. An attempt was also made to avoid repetition, to keep the overall number of sites to a minimum whilst still giving a complete picture. A series of books (including "British Upper Cretaceous Stratigraphy" ( R.N.Mortimore, C.J.Wood, R.W.Gallois) details these sites, and each site report is a justification of the particular scientific interest in a locality, of its importance in a British or international setting, and ultimately of its worthiness for conservation. The Downend Chalk Quarry at Portsdown is one such site.