Bituminization of Wood. 123 



No. 11. A bed of aluminous clay of a lighter color than those 

 above. As the low water level is only about two or three feet 

 below the upper surface of this bed, nothing is known respecting 

 its thickness, or of the nature of the beds beneath. The strata 

 associated in this formation seem to have an order of conformable 

 superposition with respect to each other, and to dip southward, as 

 the second bed of vegetable matter disappears below the low 

 water level, about two miles down the river, but I have never 

 heard of their cropping-out in any place north of this. What 

 may be the extent of country underlain by these subterranean 

 forests, I have no data to judge from ; as no excavations have ever 

 been made in the neighboring country, deeper than the wells, 

 which go only as deep as the bed of sand, marked No. 2, which 

 rests on the blue clay, No. 3 ; and the only chance of obtaining 

 sections of any depth, is where the river is encroaching on the 

 bluff. This is not a very common case in this immediate portion 

 of country, as the line of bluffs is not generally very near the 

 river banks, but separated from them by an intermediate strip of 

 level, swampy land, sometimes several miles broad, the surface of 

 which is about as high as the high water level. A bed of vege- 

 table matter, very similar to the thin bed, marked. No. 4, is to be 

 seen projecting from high banks in the vicinity of Jackson, (four- 

 teen miles from Pt. Hudson,) and as its situation is the same as 

 that, relatively to the blue clay, it is probably continuous. 



No remains of animals have yet been found in any of the beds 

 of this formation, although it is but reasonable to expect that they 

 will be found ; and I look forward in hopes that a deep cut, which 

 is to be made through the bluff for the passage of the railroad 

 which ends there, may afford better opportunities of becoming 

 acquainted with the contents of the deposits. 



A circumstance perhaps worthy of some farther notice is the 

 peculiar soft condition of the wood, previous to flattening and 

 transformation into coal, as it may be the means of saving some 

 geologists the trouble of accounting for the enormous pressure 

 they have thought necessary to the production of this effect. 

 The fact that this state seems always to precede the transforma- 

 tion into coal, would appear to favor the opinion, which is per- 

 haps the prevalent one, that it is only during incipient decompo- 

 sition, and perhaps during this pecuhar soft state, that the woody 

 fibre is ever replaced by any other kind of matter. If we adopt 



