Elements of geology / by Charles Lyell.

  • Charles Lyell
Date:
1838
Catalogue details

Licence: Public Domain Mark

Credit: Elements of geology / by Charles Lyell. Source: Wellcome Collection.

    53/582 page 23
    be volcanic eruptions here and there; but the great mass may not undergo such an alteration as to be regenerated and composed of new rocks. As all the crystalline rocks may, in some re- spects, be viewed as belonging to one great family, whether they be stratified or unstratified, it will often be convenient to speak of them by one com- mon name. But the use of the term primary would imply a manifest contradiction, for reasons which the student will now comprehend. It is indispensable, therefore, to find a new name, one which must not be of chronological import, and must express, on the one hand, some peculiarity equally attributable to granite and gneiss (to the plutonic as well as the altered rocks), and, on the other, must have reference to characters in which those rocks differ, both from the volcanic and from the unaltered sedimentary strata. I have proposed in the Principles of Geology the term 44 hypogene ” for this purpose, derived from two, under, and yivo^oa, to be born; a word implying the theory that granite, gneiss, and the other crys- talline formations are alike nether-formed rocks, or rocks which have not assumed their present form and structure at the surface. It is true that all meta- morphic strata must have been deposited originally at the surface, or on that part of the exterior of the globe which is covered by water; but, accord- ing to the views above set forth, they could never
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