This report presents the results of research done in and around the Chalbi basin, Marsabit district, Kenya, from 1982-1984. The broad objective of this research was to trace evidence of past environmental conditions, and in particular to establish whether a fresh-water 'Lake Chalbi' existed in what is now the Chalbi playa, during the Upper Pleistocene to Holocene. Fieldwork was carried out on four occasions: July-August 1982, January-February 1983, August 1983 and December 1983-January 1984. A number of specimens of volcanic and sedimentary rocKs were collected, as well as fossil bone, shell, fossil wood, pottery and stone tools. Some analysis of this material has been done, and is referred to where appropriate later in the report.