97 THE ANCIENT VOLCANOES OF DERBYSHIRE. 
denudation, continued through centuries of time, we find much the 
same condition of things in volcanic districts of the past. A notable 
example occurs in the Auvergne district of Central France. Here 
portions of the ancient cones and craters are still actually to be seen. 
In Antrim, also, where the voleanoes were probably active at 
about the same time as those of Auvergne, I have observed frequent 
examples of sections of Volcanic vents, showing crater and orifice 
filled with solidified lava and voleanic bombs, as fresh as if they had 
cooled down but a short time ago, instead of hundreds of thousands 
of years. 
But the Volcanoes of Antrim and Auvergne were but of yesterday 
compared with those of Derbyshire, and it would be unreasonable to 
expect to find the evidences quite so apparent in this country. Cones 
and craters have entirely disappeared; but the lava streams, the in- 
trusive dykes, the beds of ash, the deposits of fragmentary matter 
produced by explosive force are still with us; and even two remark- 
able instances of voleanic necks remain to testifiy to the time when 
they formed the centre of cones that probably rose many hundreds 
of feet above the level of the surrounding country, and sufticiently 
near to Burton to disturb the equanimity of its inhabitants, suppos- 
ing they had lived at that time. 
Although recognised as of volcanic origin by earlier observers, 
it was not until about the middle of the 19th century that the ‘‘Toad- 
stones ” (the local name applied to the igneous deposits of Derbyshire) 
were scientifically studied. The illustrious De la Beche gave consid- 
erable attention to them, and concluded that they were formed by 
submarine volcanic action: that the ‘‘Toadstones” were, in fact, 
lava-flows poured out over the floor of the ancient sea in which the 
carboniferous limestone was formed. This conclusion was arrived at, 
probably because De la Beche did not chance to meet with the beds 
of Tuff which are now known to exist, and which are of sub-aerial 
origin. In 1861 Jukes discovered these, and the results of his inves- 
