42 MR. E. W. BINNEY ON THE ORIGIN OF IRONSTONES. 



the earth's surface, during the formation of coal, was shewn 

 to be a shallow sea, in which grew successive crops of rank 

 and luxuriant vegetation. The waters of this sea were more 

 or less charged with mud, according to the currents flowing 

 in it. In such mud, sesquioxide of iron would necessarily 

 be present, some of it arising from the degradation of pre- 

 existing rocks, and some from volcanic sources, like that 

 from Mount Vesuvius, previously alluded to. Now both 

 nodules of argillaceous and beds of blackband ores are found 

 in fine grained argillaceous strata, shewing gentle currents of 

 water, as the size of the mineral particles composing them 

 prove. The former are often aggregated around a piece of 

 vegetable matter, or the remains of shells or fishes, which 

 appear to have had some power of attracting the iron from 

 the surrounding mud, and the latter are mixed with a mass 

 of the remains of plants, shells, and fishes. 



Now, how has the sesquioxide of iron been converted into 

 the carbonate of protoxide ? 'f his is well shewn on a small 

 scale at the bottom of our ponds and waters, full of the 

 nympheea alba, or common water lily. Into these places 

 waters containing more or less per oxide of iron flow, but the 

 roots of the plants and other decomposing vegetable matter 

 soon rob the iron of a dose of its oxygen, and convert the 

 sesquioxide of iron into the protoxide, as Dr. Lyon Flayfair, 

 C.B., F.R.S.,* in a case shewing the origin of a peat bog at 

 Downholland, in Lancashire, alluded to by the author, admi- 

 rably shews. He says, " A curious case is pointed out by 

 Mr. Binney in Lancashire, where there is evidence of a bank 

 having been thrown up by the sea at the margin of one of 

 those forests antecedent to its destruction. The effect of a 

 bank thrown up at the margin of a forest must be to stop the 



• On the Gases evolved during the Formation of Coal. Memoirs of the 

 Geological Survey of Great Britain and Ireland, and of the Museum of Economic 

 Geology in London, Vol. I., p. 478. 



