2S0 ^n Essay oti Rents. [April, 



tabular rents from which the metallic matter could proceed, and 

 as the arrangement of this matter in these rents is such as to show 

 most distinctly that it lias not been deposited from a solvent which 

 might once cover the earth, nor has been forced into its present 

 situation from below in a fluid state ; so its existence in these rents 

 embarrasses verv much the speculator on the source of the matter in 

 them. But as the metallic masses are associated with the earthy, 

 which 1 have shown to |)roceed from the contiguous matter, 1 

 would be very mucli inclined to suppose that the metallic matter has 

 the same source. But although the mechanical part of the process 

 admit? of proof, yet the chemical part is diflicult to reconcile with 

 the present principles of chemistry. Still, however, from my 

 knowledge 6f the mutual arrangements of the earthy and metallic- 

 tabular masses, I will venture to hazard the conjecture, that some 

 profound chemist will discover much nearer relations between the 

 internal properties of metallic and earthy matter than we are at 

 present aware of. 



SECOND DIVISION. 



Tlie Arrangement of that Matter in Bended-Tahular Rents which 

 entered them at the Earth's Surface, 



Although the matter in the most of bended-tabular rents is 

 similar to, and has proceeded from, that in which they are situated, 

 yet into some of them it has entered fiom the earth's surface, in 

 either a fluid or a solid state. 



The matter which entered these rents from above in a fluid state 

 is green-stone, basalt, porphyry-slate, &c. Many of the rents so 

 filled contain throughout matter of one denomination ; but a few of 

 them of two or three denominations. Rents filled from above with 

 the matter of green-stone, basalt, &c. are frequently found in the 

 coal, red, and white sand-stone formations, and are abur/lant in 

 many parts of Scotland, in these and some other formations. 



When the rents so filled were formed, the matter in which they 

 arc situated was so near its present state of solidity that no matter 

 from that source could be forced into them by the incumbent 

 weight. Thev, therefore, remained empty, till fluid substances, 

 by a part of which they are filled, travelled over them to take their 

 situations in lower parts of tlie same formations, or iii others which 

 are on lower levels ; and in doing so, matter entered, 'and then 

 filled them to the earth's surface. 



Bcndcd-tabular rents, filled with matter which entered them in a 

 solid state, contain clay, sand, gravel, and stones, either separate 

 or mixed together. A few of them are found in almost every for- 

 mation of coal. Such rents were formed at the same time as those 

 containing green-stone, &c. ; but as these fluid substances did not 

 travel over them, they remained empty till filled by the process 

 which produced the alluvial matter, bv a part of which they are 

 filled. 



