378 Darwin aiid Geology 



matter, obtained later, and a woodcut. This little paper was confined 

 to observations made in his uncle's fields in Staffordshire, where 

 burnt clay, cinders, and sand were found to be buried under a layer 

 of black earth, evidently brought from below by earthworms, and to a 

 recital of similar facts from Scotland obtained through the agency of 

 Lyell. The subsequent history of Darwin's work on this question 

 affords a striking example of the tenacity of purpose with which 

 he continued his inquiries on any subject that interested him. 



In 1842, as soon as he was settled at Down, he began a series of 

 observations on a foot-path and in his fields, that continued with 

 intermissions during his whole life, and he extended his inquiries 

 from time to time to the neighbouring parks of Knole and Holwood. 

 In 1844 we find him making a communication to the Gardener's 

 Chronicle on the subject. About 1870, his attention to the question 

 was stimulated by the circumstance that his niece (Miss L. Wedgwood) 

 undertook to collect and weigh the worm-casts thrown up, during a 

 whole year, on measured squares selected for the purpose, at Leith 

 Hill Place. He also obtained information from Professor Ramsay con- 

 cerning observations made by him on a pavement near his house in 

 1871. Darwin at this time began to realise the great importance of 

 the action of worms to the archaeologist. At an earlier date he appears 

 to have obtained some information concerning articles found buried on 

 the battle-field of Shrewsbury, and the old Roman town of Uriconium, 

 near his early home; between 1871 and 1878 Mr (afterwards Lord) 

 Farrer carried on a series of investigations at the Roman Villa dis- 

 covered on his land at Abinger ; Darwin's son William examined for 

 his father the evidence at Beaulieu Abbey, Brading, Stonehenge 

 and other localities in the neighbourhood of his home ; his sons 

 Francis and Horace were enlisted to make similar inquiries at 

 Chideock and Silchester ; while Francis Galton contributed facts 

 noticed in his walks in Hyde Park. By correspondence with Fritz 

 Miiller and Dr Ernst, Darwin obtained information concerning the 

 worm-casts found in South America ; from Dr Kreft those of Australia ; 

 and from Mr Scott and Dr (afterwards Sir George) King, those of 

 India; the last-named correspondent also sui)plied him with much 

 valuable information obtained in the South of Europe. Help too 

 was obtained from the memoirs on Earthworms published by Perrier 

 in 1874 and van Hensen in 1877, while Professor Ray Lankester 

 supplied important facts with regard to their anatomy. 



When therefore the series of interesting monographs on plant- 

 life had been completed, Darwin set to work in bringing the in- 

 formation that he had gradually accumulated during forty-four years 

 to bear on the subject of his early paper. He also utilised the skill 

 and ingenuity he had accjuired in botanical work to aid in the 



