He chose to divide the work into two separate projects, on the antiquities and the natural history of the county respectively. The work on the antiquities (which he entitled "Hypomnemata Antiquaria") was closely modelled on Dugdale, and was largely finished by 1671: Aubrey deposited his draft in the Ashmolean Museum in two manuscript volumes. Unfortunately, one of these was withdrawn by his brother in 1703 and subsequently lost. He then turned to the county's natural history. Some of his interim observations were read to the Royal Society in 1668 and 1675–6. In 1685 Aubrey recast the work, now modelling it on Robert Plot's "Natural History of Oxford-shire" (published in 1677); and it was effectively finished by 1690–91, when he transcribed a fair copy. Shortly afterwards the Royal Society commissioned another transcript, at a cost of £7. In 1693 Aubrey asked his brother William Aubrey and Thomas Tanner to bring the project to completion, but despite their best intentions they failed to do so.