Cropmarks in the Tiber valley: research into the use and occupation of the Tiber valley near Crustumerium in Roman times. This paper reports on a short field campaign aimed at investigating an extensive crop-mark identified in aerial photography by the first author. The cropmark is situated in the Tiber floodplain near the ancient settlement of Crustumerium, north of the centre of Rome and close to old riverbanks of the river Tiber. Surface finds, coring and geophysical mapping suggest that the cropmark indicates the buried remains of a substantial building complex of probably Roman Imperial date. This is an important discovery, which contributes to our understanding of the palaeogeography, sedimentation regime and settlement history of the Tiber floodplain. In this paper we limit ourselves to an initial (and speculative) interpretation of the cropmark in terms of its extent and individual components. The fieldwork was carried out in the framework of the Crustumerium project of the Groningen Institute of Archaeology, in collaboration with the Archaeological Superintendency of Rome.
