Note 10 — Chapter III

Prof. M. Bertrand in a suggestive paper published in 1888 dealt with the general order of appearance of eruptive rocks in different provinces of Europe. But the materials then at his command probably did not warrant him in offering more than a sketch of the subject, Bull. Soc. Geol., France, xvi. p. 573. In the same volume there is a paper by M. Le Verrier, who announces his opinion that the eruption of the basic rocks takes place in times of terrestrial calm, while that of the acid rocks occurs in periods of great disturbance, op. cit. p. 498. Compare also Prof. Brögger, Die Eruptivgesteine des Kristianiagebietes, ii. p. 169.