This paper discusses the lithostratigraphy, biostratigraphy and depositional sequence stratigraphy of the sandstones within the late Aptian Sola Formation in the Central and Northern North Sea (UK sector). The genesis and age of these sandstones are discussed and three depositional models are proposed These sandstones have reservoir potential, and art exploration strategy is discussed in part two of this paper (referred to hereafter as Crittenden et al., in press). We interpret these sandstones to be the product of mass-flow sedimentary? processes initiated by a tectonically-induced major fall in relative sea-level during the late Aptian, Sediments, including sands, which accumulated on the shelfal and shelf/slope break areas of the North Sea during the early Aptian relative sea-level high were subsequently reworked and eroded; together with the products of erosion of the bedrock geology, they were transported down-slope into deeper-water basinal depocentres during the late Aptian.