Although in 1931 Percy Raymond opened and briefly excavated another quarry about 20 metres (66 ft) above Walcott's "Phyllopod bed", there was very little interest in the Burgess Shale fossils from the 1930s to the early 1960s, and most of those collected by Walcott were stored on high shelving in back rooms at the Smithsonian Institution.[7] Between 1962 and the mid-1970s Alberto Simonetta re-examined some of Walcott's collection and suggested some new interpretations.[7][8] Beginning in the early 1970s Harry Whittington, his associates David Bruton and Christopher Hughes, and his graduate students Derek Briggs and Simon Conway Morris began a thorough re-examination of Walcott's collection.