Taking the volcanic rocks of this district as a whole, I regard them as the mere edges of sheets that have flowed from vents which not improbably lie concealed somewhere along the centres of these old Permian valleys. No visible necks have been described from any part of the area, and though I have not examined the whole of it, nothing of that nature was detected by me either in the Crediton Valley or between Silverton and the Exeter neighbourhood. The Tiverton district, which has not yet been searched, appears to be the only tract where any chance remains of finding some of the vents. No indication of any sills has been met with among the Devonshire Permian rocks. None of the lavas which I have seen have the internal characters of true sills, while in the field their association with the sandstones and breccias in no observed case points to intrusion. Though much remains to be done in this region before an adequate account can be given of the interesting series of eruptions which concludes the long volcanic history of the South-west of England, enough is known to indicate the general character of the phenomena. The eruptions were on even a feebler scale than those of the Permian period in Scotland, but they seem to have resembled them in their general character. Small puy-like vents were opened, from which dark scoriaceous lavas and showers of gravelly tuff and stones were discharged over the floor of the inland sea or lake-basin in which the red sandstones and breccias were accumulated. These outflows and explosions took place too, as in Scotland, towards the beginning of the deposition of the red strata, and entirely ceased long before that deposition came to an end. In each area the eruptions mark the close of Palæozoic volcanic activity in Britain. The varied and recurrent volcanic episodes which distinguished each successive geological period from the Archæan onwards now definitely terminate, not to be resumed until after the passing of the whole of the vast cycle of Mesozoic ages. 2. ERUPTIVE ROCKS IN THE MIDLAND COAL-FIELDS