[4] On the other hand, certain beds of ash and other volcanic ejecta occur in the uppermost strata of lake deposits of Limagne, so that these may indicate the commencement of the period of eruption, as suggested further on.
[5] Only very closely; for Mr. Scrope considers that the crater-cones of the chain of the Haute Loire give evidence of a somewhat earlier epoch of activity than those of the Puy de Dôme, as they have undergone a greater amount of subaerial erosion.
[6] The extent of this river erosion has been clearly brought out by Scrope, and is admirably illustrated by several of his panoramic views, such as that in Plate IX. of his work.
[7] Scrope, loc. cit., p. 147.
[8] Scrope, loc. cit., p. 144.
[9] Scrope gives a view of these remarkable basaltic cliffs in Plate XII. of his work, from which the above account is taken. At one spot near the village of Le Gua there is a break in the continuity of the sheet.
[10] See Scrope, loc. cit., p. 181; also Appendix, [p. 228]. While there is no primâ facie reason for questioning the origin of the Demise skull, yet from what Lyell states in his Antiquity of Man, p. 196, it will be seen that he found it impossible to identify its position, or to determine beyond question that its interment was due to natural causes. But assuming this to be the case, he shows how the individual to whom it belonged might have been enveloped in volcanic tuff or mud showered down during the final eruption of the volcano of Demise. MM. Hébert and Lartet, on visiting the locality, also failed to find in situ any exact counterpart of the stone now in the museum of Le Puy.
[11] See Daubeny, Volcanoes, p. 31.
[12] That is to say, the surfaces of the lava-streams are not at all, or only slightly, decomposed into soil suitable for the growth of plants, except in rare instances.
[13] 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.