Of rocks whose age is more uncertain, but which are probably of Precambrian age, those of Charnwood Forest in Leicestershire may first be noticed. They are largely of pyroclastic origin, and from their likeness to similar rocks of proved Precambrian age, they are very probably of this age, as suggested by Messrs Hill and Bonney[59]. A group of crystalline schists is found in the south of Cornwall, especially near the Lizard, and similar rocks are found in the Channel Isles. As their relationship to newer rocks is not clear, little can be said about them, which has not already been noticed in mentioning the crystalline schists of other regions[60]. [Footnote 59: Hill and Bonney, _Quart. Journ. Geol. Soc._, vol. XXXIII. p. 754, XXXIV. p. 199 and XLVII. p. 78; see also Watts, W. W., _Rep. Brit. Assoc._ for 1896, p. 795.] [Footnote 60: For an account of the Volcanic History of Britain in Precambrian times, see Sir A. Geikie, Presidential Address to the Geological Society, _Quart. Journ. Geol. Soc._, vol. XLVII. p. 63.] The Precambrian rocks of the European continent consist largely of crystalline schists which in their general aspects recall those of the north-west Highlands of Scotland. Important masses are found in Bavaria, Bohemia, France, Spain, Scandinavia and Russia. The Scandinavian and Russian rocks of Archæan type are in places succeeded by the _Olenellus_-bearing beds of the Cambrian rocks, and rocks of Eparchæan character are not extensively developed, though certain Norwegian rocks may be the equivalents of the Torridonian rocks of Scotland, and other rocks of this type are found in places in Sweden. In Bohemia and in Brittany Precambrian strata of Eparchæan type have been discovered, and this type probably occurs elsewhere in Europe. The North American rocks require some notice, for it was in Canada that the existence of Precambrian rocks was first recognised, and the term Laurentian, originally applied to an Archæan type of Precambrian rocks in Canada, was subsequently adopted in speaking of many Precambrian rocks elsewhere, though it is now wisely restricted to the type of rock in the original area to which the name was first given. These Laurentian rocks acquired a special, interest on account of the occurrence in their limestones of a supposed reef-building foraminifer, _Eozoon canadense_, but detailed study of its structure and mode of occurrence has convinced most geologists that the structure is inorganic.