A drilling and trenching exploration of the ilmenite deposits at Piney River furnished maps and material for a re-study of the origin of the deposit. It seems to be a segregated dike intrusive into the earlier, closely related anorthosite. Later hydrothermal attack is widespread, but does not appear to have increased the percentage of titanium in the deposit explored. This leads to a discussion of the use of the term replacement, and some other terms, applied to ore deposition. If the terms are used carelessly or without adhering to the usual definition, the misinterpretations may cost later students much time and effort.