VOL. XLI.] PHILOSOPHICAL TRANSACTIONS. 407 



frost-work, and incrusted plants, are some of them so very delicate and tender, 

 as to make it impracticable to bring them away with half their beauty, by the 

 most careful conveyance. In one place there is an ivy creeping along the rock, 

 part of it entirely petrified, another part only incrusted, and a third still 

 vegetating. In another place is a hazle-tree, its root composing part of this 

 petrified mountain, the branches some petrified, and some tenderly incrusted. 

 As these are changed, others spring up, and in time will undergo the same fate. 

 In short, nothing in nature can give a more clear idea, or more beautiful re- 

 presentation, of the whole business of petrifaction, than a curious observer will 

 see, and frame in his mind from this mountain. He will see, that not only the 

 water, as it distils out of the rocks, is capable of incrusting and petrifying the 

 bodies it meets with in its passage, but that even the streams and exhalations, 

 being highly saturated with these mineral particles, will produce the same efl^ect; 

 as is evident in the place under consideration, and will generally best account 

 for the supply of petrifying matter, brought to fill up the vacuities left by the 

 decay and waste of vegetables incrusted over; and which in course of time are 

 constantly filled with it. For though the water of some springs may be so 

 loaded with mineral matter, as, perhaps by penetrating the pores of wood and 

 other lax bodies, to increase greatly their specific gravities ; yet surely it is con- 

 trary to the laws of matter, and absurd to say, there is any hidden property in 

 such waters, capable of changing the parts of one body into another, specifically 

 different. It may in time, no doubt, lose its texture and coherency, by the 

 admittance of heterogeneous particles of different attractions ; but the cause of 

 coherency in the parts of the original body must entirely cease, and be dissolved, 

 before it can be said to become a part of any other body whatever. Afterwards, 

 indeed, the space that was possessed by the parts of the original body, may be 

 supplied by those of the new one, so as to make in time a uniform stone, in the 

 shape of the original plant : but if this petrified plant be still kept in the place 

 where the same petrifying quality continues to act upon it, it will lose even that 

 shape, and become a part of the body it is contiguous to ; and so a great many 

 of these petrified plants, and other bodies united together, will compose large 

 masses, and whole strata of stone. This is clearly the case in the instance now 

 before us, and perhaps it might be carried so far as to strengthen our concep- 

 tion about the general formation of the strata of lime- stone or marble ; that 

 appearing to be every where, (notwithstanding Dr. Woodward dispatches them 

 much more expeditiously) but especially in the Peak of Derbyshire, such a 

 petrifaction as above described, quite finished. I could urge many reasons for 

 my supposition, but I will not trouble you with them here, the cou)pass of this 

 letter not permitting me ; nor do I know how far such conjectures are capable 

 of being used, with regard to the received opinion of the world's age; but if 



