Note 10 — Chapter XVIII
Reading edition
Olivine is known to accompany basaltic in opposition to clinkstone rocks. Gmelin says, “Natron and potash characterize clinkstone; iron and magnesia, basalt.” “Magnesia and iron show a great tendency to enter into combination with each other.” These two latter substances are main constituents of meteoric stones, while the alkalies are generally present in very small quantities. Gmelin on Clinkstone, Edinburgh New Philosoph. Journal, April, 1829.