Simon Callery's new exhibition at Dover Castle raises the question of 'what is archaeology?' It offers sideways on, a long sectional slice of chalk rock, a 'dip' within which shards may be found. Such installation works as Callery's (which they undoubtedly are in genre) raise welcome new issues of the definition of art, landscape and materiality. Hopefully, these fruits of excavation will travel to London and points north. Callery's accompanying trays full of photographs lend an air of authentic museology which, without subterfuge, sustain the overall authenticity of the venture, and of the artist's immediate intentions.