A meeting on Biota and palaeoatrnospheres was held at the Geological Society’s apartmenfs at Burlington House on 19 December 1987. It was a joint Ordinary Meeting with the Linnean Society and the Palaeontological Association. This symposium formed part of the celebrations of the Linnean Societ of London, and was held on the eve of its bicentenary year of 1988. The Linnean Society had elected to hold a series of joint meetings with other Societies with allied or overlapping interests, and the Geological Society was an obvious choice. The two societies have been linked physically, by occupying adjoining premises in Burlington House, but more importantly by shared Fellowship, from the earliest days of their co-existence in the present rooms. The principal common ground of the two Societies lies largely in palaeontology and so it was appropriate that plans for a joint meeting should also have involved the Palaeontological Association, which in turn shares membership with both the Geological Society and the Linnean Society. It was, in this way, that the three bodies came to convene a symposium which was to reflect some aspect of their common interests. The organizers decided to try to avoid any of the aspects of conventional palaeontology, but rather sought out a topic which would bring together biologists and geologists on less well-worn ground. The theme of the interaction of the atmosphere and biota through time was chosen as one which fulfilled this aim, but one which was also topical. The recently initiated International Geosphere–Biosphere Programme has