24 : T. S. Hunt on Voleanie Action. 
forms the elements of the sedimentary strata, with an evolution 
of heat as a result of the chemical process ( Naturgeschichte, vol. 
i, p. 109; also Bull. Soc. Geol. de France oe vol vii, p. 197). 
In commenting upon these views (Am. Science, July, 
1860), I have “remarked that, by she ci incandescent 
nucleus as a source of heat, Keferstein has excluded the true 
exciting cause of the chemical changes which take place in the 
buried sediments. — notion of a subterranean combustion or 
fermentation, as a source of heat, is to be rejected as irrational. 
A view identical cits “ae of Keferstein, as to the seat of 
voleanic phenomena, was soon after put forth by Sir John 
Herschel, in a letter to Chases Lyell, in 1836 (Proc. Geol. 
ay g from the suggestion of Scrope 
and d Babbage that the Sotconat horizons in the earth’s crust 
rise as a consequence of the accumulation of sediments, he 
ined that mie buried strata will thus become ¢ —E stallized 
Herschel was farstnrs ignorant of the extent to which his views 
had been anticipated by Keferstéin; and the suggestions of the 
one and the other seemed to have passed Pagipesnen by geologists 
— in E Marek se I Rene, them in a paper read before 
ar tinder the influence of a tat: temperature “in sediments 
permeated with water, and containing, besides -siliceous and 
aluminous matters, carbonates, chlorids, and carbonaceous sub- 
stances. From these, it was shown, might be produced all the 
gaseous emanations of volcanic districts, while from aqueo- 
‘ eous fusion of the various oo es might result the great 
variety of eruptive rocks. uote the words of my pape 
just referred to: “We ase that the earth’s solid cs of 
. anhydrous and pve igneous rock is everywhere deeply 
concealed beneath its own ruins, which form a great mass of 
sedimentary strata, permeated by water. As heat from beneath 
invades these enna it produces i in them that change which 
constitutes normal metamorphism. These rocks, at a sufficient 
