The University of Amsterdam conducted extensive archaeological research in Midden-Delfland in the years 1991-1999. Seven micro-regions were studied via monitoring work, trial trenches and excavations. Several indigenous Roman settlements and a large scale Roman field system were identified. Three sites (MD 01.23, 20.17 and 21.15) yielded traces that were interpreted as cattle corrals (Van Londen 2006, 34-49, 138-142, 134-136). They were located in isolated parts of the site where traces of buildings were virtually absent. The U-shaped structures and vague impressions of hoof-marks have resulted in the interpretation as areas for keeping livestock. Another interpretation is however plausible, particularly for the MD 21.15 structure (fig. 5D). This three-sided structure measures approximately 7 by 6 m and is situated east of a silted up channel. The finds included six fibulae as well as hand-shaped pottery. Part of a hand-shaped pot was found in situ in a pit at the end of an immediately adjacent ditch. The entire complex of features and finds is at least unusual for a corral or outbuilding. The faint traces within the structure were interpreted as hoof-marks on a basis of similarity to the impressions found at site MD 20.17. They are however far from convincing as such, and could easily be interpreted as traces of poles or stakes. Taking everything into account, it appears that this building was not a cattle corral but the locus of rural cult.