On the Idenliiy of Silex and Oxygen. 67A 



thalk, marble, lime-stone, and other fossil bodies, of which 

 carbonate of lime forms an extensive portion, so much so, 

 as to render this class of minerals extremely importatit in all 

 , geological discussions. 



This singular coincidence has not escaped notice, and 

 many very respectable men have advanced opinions Upon the 

 subject. It has, indeed, been supposed, that there is £t 

 transmutation of one of these elements into the othef, or 1 

 graduation of lime into silex ; and it is asserted that th6 

 recent formation of flint had been perceived, near the sur- 

 face, in a calcareous mountain, in which, also, animal and 

 vegetable substances were found petrified by the silex ^ 

 and that rhomboidal crystals were likewise present, passing 

 from the state of carbonate of lime to nearly pure silex. 



It is evident, such a theory as this is not tenable, but 

 must be involved in difficulty, since it assumes a case, of all 

 others, the most improbable ; for, according to these pre- 

 mises, wc are compelled to admit, that the diamond, the 

 oxygen and the lime, that is to say, the real ingredients of 

 the chalk, all contribute to the formation of sileX, which is, 

 avowedly, one of the most perfectly indecomposable of ele- 

 mentary bodies, and, certainly, much more so than lime* 

 This conversion of lime into silex is, I presume, quite in- 

 consistent with general facts, and contrary to every object 

 in nature which contains these two ingredients among its 

 constituent principles. 



In chalk particularly, which is one of the most plentiful 

 of nature's productions, as well as in all the other carbonates 

 oF lime, there is, usually, a very copious assortment of srlex, 

 under one shape or another ; and this is either so intimately 

 blended as to be hardly perceptible to the sight, and, often, 

 can only be extracted by analysis ; or it occurs in the form 

 of sand, gravel, or what, in common terms, are called^z/z/- 

 stones» It is necessary to observe, that these stones are 

 chiefly of an obtuse and rounded figure, and never pointed 

 and angular; they are frequently found alone, and, from 

 their appearance and other circumstances, seem to have 

 suffered a. diminution of ihf^ir original bulk, by yielding up 



S"^ a portion, 



