Some of the more leisurely sightseers in the National Capitol make the pilgrimage to the Rock Creek Cemetery not alone to see the Adams monument of Saint Gaudens but to examine the marble tombstone which has become bent during the course of years due to being supported on four posts under the ends but left without support in the middle. The stone is 180 cm long, 90 cm wide and 5 cm thick, and the sagging amounts to some 8 cm. The amount of sag makes any effect due to solution or weathering inadequate as an explanation. That the phenomenon cannot be due to a simple elastic deformation seems equally beyond question, for had the workmen who put the stone in place eighty years ago noted a three inch sag they would undoubtedly have supported the middle part.
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Eugene C. Bingham (1932) studied this question.