Former top-secret papers containing a geological analysis of D-Day invasion beaches have been rediscovered among Birmingham University archives.
Research reports, maps, photographs and the transcript of an interrogation of a German army geologist are among the documents recently found during re-classification of the university's Lapworth Museum collections.
Papers detailing the results of geological surveys of the beaches in Northern France played a vital part in the Allies' choice of landing sites.
They were the work of Fred Shotton, Birmingham's former vice-principal and Lapworth professor of geology.
Professor Shotton, who died in 1990, flew over the beaches himself in the Spring of 1944 as part of the research, which also involved many dangerous sorties in Normandy, to collect samples of sand and deposits for analysis.
Jon Clatworthy, curator of the Lapworth Museum, said: "Fred told the tale of his excursion in a modified mosquito aircraft over occupied France. He was able to lie in the base of the fuselage observing the beaches through a specially fitted glass panel."
On one of the excursions a piece of equipment, called an auger and used to make boreholes to obtain sediment samples, was left behind.
Mr Clatworthy said: "No one wanted the Germans to know which beaches they might use for the landings, so there was some discussion of a plan to drop augers on all the beaches from Norway to Biscay - until it was realised that there weren't enough augers."
Professor Shotton and his team chose Brancaster in Norfolk as the beach in England most comparable to the geological make-up of those in Normandy.
The beach was bombed to test what effect craters washed over by seawater would have on the mobility of landing vehicles.
The archive will be on display at the Lapworth Museum at the university's School of Geography, Earth and Environmental Sciences from Saturday.