The literature dealing with Irish mineralogy is rather extensive, much more so than might be at first thought, but it is of such a scattered nature that to obtain at present anything like a complete account of the minerals which occur in this country, or in any particular portion of it, would involve much time and labour in hunting up the publications containing the various records. The need of some authentic work of reference on the subject, revised to date, was often felt by the writer, who some years ago set to work to collect together all the data available, both from published records and by means of a personal examination of such public and private collections of minerals in this country as he could gain access to.