In every runnel and crevice and slip and patch,
A powdery rubble of pumice, black and red,
Flakes of cooled lava and stones congealed from fire.
It was no dream. A butterfly spread its fans
White, veined with green, on a rock of sunlit slag,
Slag of the seething furnaces below.
They reached the summit; and, under them, beheld
The hollow cup, the crater, whence that flood
Out of the dreadful molten heart of the earth
Poured in red fury to create Auvergne.