During the last three years I have at various times collected and studied rocks from the Lake District. Some of them are, I think, of sufficient interest to render them worth describing. It is my opinion that a great deal of very interesting petrological work still remains to be done among these rocks, and that when they are more studied in detail they will be found to present more diversity of type than is usually supposed.I will first note the occurrence of a variety of rock not previously recorded in this district. It is a quartz-andesite, or dacite. It is exposed on the ridge between Greenburn and Wytheburn, not very far from Dunmail Raise, and near to a new wire-fence which bounds, I believe, the property of the Manchester Waterworks. It is a dark-coloured rock, on a newly-fractured surface of which are seen numerous light spots of porphyritic felspars, and some of calcite, with many grains of quartz, some of good size. It was the grains of quartz which instantly attracted my attention to this rock when a bit was chipped off it in passing the exposed crag.