The date is established by the connection between this fragment and CD’s reading of his paper ‘Elevation and subsidence in the Pacific and Indian Oceans’ at the Geological Society of London on 31 May 1837 (see n. 2, below).

This question was one of several written down by CD for Stokes and is quoted by Stokes in his Discoveries in Australia (Stokes 1846, 1: 331); CD’s original list of queries has not been found. Stokes was a shipmate of CD’s during the Beagle voyage of 1831 to 1836, serving as mate and assistant surveyor (see Correspondence vol. 1). From 1837 to 1843 the Beagle was employed in surveying coastal areas of Australia under the successive commands of John Clements Wickham and Stokes, sailing from Plymouth on 5 July 1837 (Stokes 1846). On 31 May 1837, Stokes attended a meeting of the Geological Society at which CD read his paper ‘Elevation and subsidence in the Pacific and Indian Oceans’ (Collected papers 1: 46–9; see also Stokes 1846, 1: 331). In this paper CD proposed a theory of the development of coral reefs. For the development of CD’s theories on coral formation and subsidence, see Correspondence vol. 1, Appendix V, and Stoddart 1976. Stokes wrote (Stokes 1846, 1: 331) that his interest in the paper was greatly enhanced: by a series of queries, kindly furnished by Mr. Darwin, and drawn up with a view to confirm or invalidate his views, his purpose being to elicit truth from a combination of well attested facts, and by inducing the research of others to further the objects of science. In June 1839 Stokes discovered a raised beach of coral and shells on the coast of Cape Upstart that he argued, following CD’s theory, supported the view that the north-east coast of Australia had not been subject to subsidence (Stokes 1846, 1: 332–3). CD published a full account of his theory in 1842 (Coral reefs), and acknowledged Stokes for supplying information on Australian coral (ibid. p. 86).