Through the research on COBWEB and CLASSIT，this paper presents a new representation method of numeric attributes．This method represents numeric attributes based on its value distribution．The relative problems and properties of clustering in this representation are discussed in detail．This paper also proposes a clustering evaluation function which can deal with both symbolic attributes and numeric attributes uniformly．A concept formation system CFLS(concept formation learning system)has been implemented and applied to geological classification area．CFLS is also introduced in this paper．