The vast majority of vertebrate fossils occur in cannels, in cannel-like shales, or in nodules of ironstone imbedded in thick shales. They are most likely to be found in the roof of a coal seam, but they may be found elsewhere. The southern end of the North Staffordshire field is perhaps the most hopeful area. But fossils found there are likely to be of kinds already known, while those from other places will more probably be of hitherto unknown animals. To-day the coal miners are far better educated than their grandfathers, and they are just as likely to find something of real scientific interest. Unfortunately the fossils occur in small patches, perhaps where a pool containing a number of fish dried up, and their skeletons were buried under mud. Such an area is only worked for a short time. It is very unlikely that any particular reader of Coal will find any.