248 Br. T. Sterry Hunt — On Volcanic Action. 



the equilibrium of pressure, consequent upon a transfer of sediments, 

 while the yielding surface reposes on matters partly liquefied, will 

 explain the movements of elevation and subsidence of the earth's 

 crust. Herschel was probably ignorant of the extent to which his 

 views had been anticipated by Keferstein ; and the suggestions of 

 the one and the otlier seemed to have passed unnoticed by geologists 

 until, in March, 1858, I reproduced them in a paper read before the 

 Canadian Institute (Toronto), being at that time acquainted with 

 Herschel's letter, but not having met with the writings of Keferstein. 

 I there considered the reaction which would take place under the in- 

 fluence of a high temperature in sediments permeated with water, 

 and containing, besides silicious and aluminous matter, carbonates, 

 sulphates, chloride, and carbonaceous substances. From these, it was 

 shown, might be produced all the gaseous emanations of volcanic 

 districts, while from aqueo-igneous fusion of the various admixtures 

 might result the great variety of eruptive rocks. To quote the words 

 of my paper just referred to: "We conceive that the earth's solid 

 crust of anhydrous and primitive igneous rock is everywhere deeply 

 concealed beneath its own ruins, which form a great mass of sedi- 

 mentary strata, permeated by water. As heat from beneath invades 

 these sediments, it produces in them that change which constitutes 

 normal metamorphism. These rocks, at a sufficient depth, are neces- 

 sarily in a state of igneo-aqueous fusion ; and in the event of frac- 

 ture in the overlying strata, may rise among them, taking the form 

 of eruptive rocks. When the nature of the sediments is such as to 

 generate great amounts of elastic fluids by their fusion, earthquakes 

 and volcanic eruptions may result, and these — other things being 

 equal — will be most likely to occur under the more recent formation." 

 (Canadian Journal, May 1858, vol. iii. p. 207.) 



The same views are insisted upon in a paper " On Some Points in 

 Chemical Geology" (Quart. Jour. Geol. Soc, London, Nov. 1859, 

 vol. XV. page 594), and have since been repeatedly put forward by 

 me with farther explanations as to what I have designated above 

 the ruins of the crust of anhydrous and primitive igneous roch. This, 

 it is conceived, must, by contraction in cooling, have become porous 

 and permeable, for a considerable depth, to the waters afterwards 

 precipitated upon its surface. In this way it was prepared alike for 

 mechanical disintegration, and for the chemical action of the acids, 

 which, as shown in the two papers just referred to, must have been 

 present in the air and the waters of the time. It is, moreover, not 

 improbable that a yet unsolidified sheet of molten matter may then 

 have existed beneath the earth's crust, and may have intervened in 

 the volcanic phenomena of that early period, contributing by its 

 extravasation to swell the vast amount of mineral matter then 

 brought within aqueous and atmospheric influences. The earth, air, 

 and water thus made to react upon each other, constitute the first 

 matter from which by mechanical and chemical transformations the 

 whole mineral world known to us has been produced. 



It is the lower portions of this great disintegrated and water- 

 impregnated mass which form, according to the present hypothesis, 



