Crystalline Limestone. 367 



heat may sometimes, indeed, operate as an assisting, and, as 

 it would seem, as an accelerating, agent, but which can also go 

 forward at the usual temperature. Although we not unfre- 

 quently hear from volcanists (for the facts often drive them to 

 this), that fusion was not necessary in order that the change 

 in question might take place, yet it is not to be denied, that, 

 in their mode of viewing the matter, they must think that 

 the limestone was reduced to a state of softness ere it could 

 become crystalline ; and, according to their whole line of ar- 

 gument, they are more especially compelled to adopt this sup- 

 position in the cases where various accidental minerals, such 

 as silicates, are crystallized in the mass of limestone. Now, 

 where the distinct petrifactions are met with in the marble, 

 there were likewise found various foreign crystallizations 

 which had plainly been produced simultaneously with the cal- 

 careous spar of the marble, between whose crystals they are 

 embedded. Naumann attests this fact in his " Beitrdge zur 

 Kenntniss Norwegens''' (vol. i. p. 12) ; for he says, — " We found a 

 very distinct specimen of Favosites (Calainopora) embedded 

 between fibres of tremolite." In the marble quarry of Gjel- 

 lebok, between Christiania and Drammen, garnet, zinc-blende, 

 and large masses of grammatite occur, and amongst these 

 distinct petrifactions are met with. 



If those who explain contact marble by a melting heat, flatter 

 themselves that they have struck out the only safe and really 

 legitimate path of investigation, such is, undeniably, a great 

 deception. If we consider all the circumstances of its produc- 

 tion — if we do not select certain of them, which, as regards a 

 particular view, seem to suit, and if we do not suppress the 

 others, — we do not arrive at the result, that the substance in 

 question has been melted either partially or completely. It is 

 by no means a physical or logical necessity which calls forth 

 this result, but it is the desire to possess a principle which is 

 so urgently requisite in the system adopted. It sounds well, 

 and is perfectly adapted to deceive the less skilful, when it is 

 said, — ^we found our opinion on the old chemical axiom, that 

 it is only bodies in a liquid state which can crystallize ; we have 

 on our side the fact confirmed by experiment, that melted 

 limestone consolidates into just such a crystalline mass as the 



