Note 13 — Chapter VI · EXTINCT VOLCANOES OF CENTRAL FRANCE.
Reading edition
E. G. Hull, "On the Domite Mountains of Central France," Scien. Proc. Roy. Dublin Society, July 1881, p. 145. Dr. Hull determined the density of the domite of the Puy de Dôme to be 2.5, while that of lava is about 3.0.