It has been claimed that Greenough and the Geological Society failed to work with William Smith in the production of a geological map due to snobbishness, but Rachel Lauden argues that a more compelling reason is that Greenough did not consider that fossils could reveal anything about the nature of rocks. Greenough (incorrectly) considered that fossils had been very overrated in their usefulness, as fossil species were different from modern species, so fossils could not be used to 'theorise' about or deduce the relative age and the conditions of deposition of the rocks. Indeed, he was suspicious of the concepts of 'stratum' and 'formation', much used by Smith. For this reason Greenough wanted to dissociate himself and the Geological Society map from the man who was using fossils to identify strata. Seemingly, Greenough had intellectual reasons rather than primarily social reasons for not collaborating with Smith. This did not, however, stop Greenough from using Smith's map as a source of material for the Geological Society's version of the map and there is debate about how much Smith's map influenced Greenough. Both maps now hang side by side on the main staircase in the entrance hall of The Geological Society apartments in Burlington House, London. An anonymous 1855 obituarist noted that Greenough's geology was based mainly on "mineralogical views" and that his habitual skepticism of new theories made him a "drag" on the progress of geological science.